BASIC EDUCATION ASSISTANCE FOR MINDANAO CHEMISTRY — THIRD YEAR LET'S PUT IT INTO ORDER ORDER AMONG ELEMENTS Information about this Learning Guide

Basic Education Assistance for Mindanao (BEAM) project. Prior approval must be

given by the author(s) or the BEAM Project Management Unit and the source must

be clearly acknowledged.

Information about this Learning Guide

Recommended number of lessons for this Learning Guide: 7

Basic Education Curriculum Competencies

Year 9 science: Demonstrate understanding of the properties of elements

based on periodic atomic properties.

• Name the elements given the chemical symbol.

• State the basis of the arrangement of elements in the periodic table. • Use the periodic table to predict the chemical behavior of an element.

• Relate the number of valence electrons of elements to their group number in the periodic table.

• Infer trends in atomic sizes, ionization energy, metallic and nonmetallic properties and electronegativity across the period and down the family.

Objectives

• Discuss the basis of the arrangement of elements in the periodic table. • Predict the chemical behavior of an element using the periodic table. • Relate the number of valence electrons of elements to their group number. • Describe the atomic structure of an element.

• Organize the elements of the periodic table according to their atomic mass, number of electron shells and valence electrons, then compare their order within the periodic table.

• Identify common physical uses of elements within a family.

Essential concepts, knowledge and understandings targeted

• The structure of the periodic table corresponds directly to atomic structure. This makes the table an invaluable tool for determining the property and behavior of elements and predicting how they will react.

• All the transition metals have the same number of valence electrons because electrons are added to interior shells instead of the valence shell.

• John Newlands arranged the known elements in increasing order of their atomic weight. • Mendeleev stated in his Periodic Law that the properties of elements are periodic

functions of their atomic weights.

Specific vocabulary introduced

• atomic radius - is defined as being half of the distance between the nuclei of two identical atoms joined by a single covalent bond.

• electrons - are negatively charged particles.

• element - a substance composed of one type of atom and cannot be chemically separated.

• energy levels - are regions of space around the nucleus where electrons stay.

• group - a column or group of columns in the periodic table; elements in one group have the same number of electrons in the outermost shell.

• orbitals - are regions of space above the nucleus where electrons can probably be found.

• period - a row of the periodic table; each corresponds to the number of electron shells in an atom of the elements in that row.

• periodic table of elements - an organization of Earth's elements arranged according to atomic number, the number of protons each element's nucleus contains.

• protons - are positively charged particles.

• valence electrons - the electrons contained in the outermost shell in an atom of an element; the electrons available for chemical bonding.

Suggested organizational strategies

• Preparing the physical arrangement of the room to be conducive to group activities

Opportunities for Integration

• Doing a research given aspects of an element.

• Communicating with classmates during a collaborative activity. • Writing a journal, Reading of materials

Mathematics

• Seeking for a pattern, electronic configurations,periodic table magic square Art Education

• Making element trading cards Values Education

• Cooperating in group activities

Activities in this Learning Guide

Activity 1: Save My Day!

Multiple Intelligences

Skills

• Order, group, infer causes, Translate knowledge into new context

Activity 2: Powerful Pattern

Multiple Intelligences

• Logical/Mathematical, Visual/Spatial

Skills

• Grasp meaning, Assess value of theories, presentations

Activity 3: A Historic View

Multiple Intelligences

• Verbal/Linguistic, Interpersonal

Skills

• Grasp meaning, Understanding information

Activity 4: Making Sense Of The Elements

Multiple Intelligences

• Logical/Mathematical, Interpersonal

Skills

• Solve problems using required skills or knowledge • Translate knowledge into new context, Seeing patterns

Activity 5: Element Chart

Multiple Intelligences

• Verbal/Linguistic, Interpersonal

Skills

• Understanding information, Knowledge of major ideas

Activity 6: Periodic Table Trend Game

Multiple Intelligences

• Verbal/Linguistic, Body/Kinesthetic

Skills

• Mastery of subject matter, Seeing patterns

Activity 7: Periodic Table Magic Square

Multiple Intelligences

Skills

• Solve problems using required skills or knowledge • Mastery of subject matter, Seeing patterns

Activity 8: Element Trading Cards

Multiple Intelligences

• Body/Kinesthetic, Visual/Spatial, Interpersonal

Skills

• Understanding information, Knowledge of major ideas, Use information

Activity 9: A Whole New World

Multiple Intelligences

• Logical/Mathematical, Interpersonal

Skills

• Use methods, concepts, theories in new situations, Translate knowledge into new context

Text Type

• Discussion

Key Assessment Strategies

Mind Map

The Mind Map displays the organization and relationship between the concepts and activities in this Learning Guide in a visual form. It is included to provide visual clues on the structure of the guide and to provide an opportunity for you, the teacher, to

reorganize the guide to suit your particular context.

Stages of Learning

The following stages have been identified as optimal in this unit. It should be noted that the stages do not represent individual lessons. Rather, they are a series of stages over one or more lessons and indicate the suggested steps in the development of the targeted competencies and in the achievement of the stated objectives.

Assessment

All six Stages of Learning in this Learning Guide may include some advice on possible formative assessment ideas to assist you in determining the effectiveness of that stage on student learning. It can also provide information about whether the learning goals set for that stage have been achieved. Where possible, and if needed, teachers can use the formative assessment tasks for summative assessment purposes i.e as measures of student performance. It is important that your students know what they will be assessed on.

1. Activating Prior Learning

This stage aims to engage or focus the learners by asking them to call to mind what they know about the topic and connect it with their past learning. Activities could involve making personal connections.

Background or purpose

One of the most important things to do to make our daily tasks easier to accomplish is to sort things out. This activity aims to convey the message of the importance of organizing and classifying things.

Strategy

A strategy used to brainstorm about or review a topic. It allows students to share knowledge with each other in a non-intimidating manner.

In here, students will move around giving their opinion about a topic written on the charts posted around the room.

Materials

colored marker pens manila paper

Activity 1: Save My Day!

Prepare three sheets of manila paper. Number it 1,2 and 3 respectively. Provide each sheet with a heading as follows:

Sheet 1 – Things that you organize at home ex. CD collection

Sheet 2 – Characteristic(s) you use to organize things at home ex. style of music

Sheet 3 – Write two general reasons why you organize things.

Note: Please remind the students that since not all groups follow the same logical sequence in filling up the sheets, their answers in sheet 2 will not necessarily be a follow up of their answers in sheet 1.

Post the manila paper on the walls of the room making sure that space is provided between the sheets for the students to move freely.

Divide the class into small groups.

Assign each group to one manila paper posted on the wall.

Distribute different colored marker pens to each group (e.g. Group 1-red; group 2-black; group 3-blue, etc).

Distribute the groups in such a way that each one of them has a particular topic/sheet to work on. Remind them to bring along their marker pens. Let them do the task at a given time (e.g 5 minutes). At a given signal they should move to the next sheet to do the next task. Provide direction to make the process systematic and orderly. The process continues until they return to their original station/sheet.

At the end of the activity, allow the students to visit the charts and read the various responses. If there are many sets of these sheets, organize them in such a way that all sheet 1s will be displayed together, all sheet 2s, etc.

Lead the discussion to the importance of organizing things to make tasks easier to accomplish therefore SAVING OUR DAY!

Formative Assessment

Their responses may be given points if you wish. It is not however, required that you rate the result at this stage since it is a brainstorming activity.

Roundup

2. Setting the Context

This stage introduces the students to what will happen in the lessons. The teacher sets the objectives/expectations for the learning experience and an overview how the learning experience will fit into the larger scheme.

Background or purpose

In this stage, the students will be oriented with the overview of the lesson/series of lessons.

Strategy

Brief presentation of the topic. This strategy will allow learners to see the big picture of the lesson. In this stage, it is needed to set the minds of the learners on the topic to be discussed.

Activity 2:

Explain that organizing things has lead to a big breakthrough in the field of Chemistry---- the development of the Periodic Table.

Have students share ideas about the following questions: ➢What do you know about a periodic table?

➢What can you see in it? What do those letters and numbers represent? ➢Why do you think are they arranged that way?

Inform the students that the activities that will follow will help them understand the Periodic Table and how it will be used to infer trends in atomic sizes, ionization energy, metallic and nonmetallic properties and electronegativity across the period and down the family.

3. Learning Activity Sequence

This stage provides the information about the topic and the activities for the students. Students should be encouraged to discover their own information.

Background or purpose

The Periodic Table is the source of a great deal of information about chemical elements. The following activities will help students understand the full potential of it.

Strategies

Card Game (Powerful Pattern)

Classifying and Analyzing (Powerful Pattern and Making Sense of the Elements)

Classifying is a systematic procedure used to impose order on collections of objects or events.

Analyzing is examining the contents of scientific ideas and concepts, finding patterns and relationships and to determine their essence or meaning.

The activities will engage the students in putting the numbers in order and analyze the hidden pattern.

Hot Potato (A Historic View)

what has been written and to write their own ideas on the sheet. The process is repeated until the papers get back to their starting point. All groups should be reminded that once an idea has been recorded, or an idea has been read on another sheet, it cannot be written down a second time. No repeats are allowed.

In this lesson, the historic view on the Development of the Periodic Table accompanied by questions will be given to each team. The team with the highest correct answers wins.

Tabulating (Element Chart)

A science process skill where students are instructed to extract key concepts from a given text and record it in a tabular form. It enhances the thinking skill of the students because it encourages them to look more carefully at something.

Materials for Activity 3.1

Student Activity Sheet 3.1- Powerful Pattern, page 17

Teacher Resource Sheet 1- Chips for Powerful Pattern, page 19

Teacher Resource Sheet 2- Answer Key for Chips for Powerful Pattern, page 20

Activity 3.1: Powerful Pattern

Cut out the figures found on the Teacher Resource Sheet 1- Chips for Powerful Pattern (refer to page 19) before doing the activity.

Divide the class into groups of six.

Tell the students that they are going to simulate how scientists in 1800s arranged the elements.

Distribute Student Activity Sheet 3.1 – Powerful Pattern and the chips, page 17. Let them read the instructions carefully. Make sure that they understand it. Provide 10 minutes for the activity.

Let one group present their output (because it is assumed that all of them will come up with the same pattern). Just ask the other group to share their answers to some questions. In case another pattern comes out, let the group justify their answer.

Process the information by giving these key points:

• Remind the class that solving a problem in Science is like solving a puzzle. Empty cells or vacant spaces can be as informative as known information, just like in their activity. Discuss the patterns shown on the grid.

• Ask them what came to their mindwhen they first saw the numbers written on the cards.

• Tell them that a similar situation existed among chemists in the mid-nineteenth century. As more and more elements were being discovered, scientists soon found themselves with a lot of data on each individual element, but no real way to make sense of the information. The next activity will give you an idea as to the studies made by the scientists.

Proceed to the next activity.

Materials for Activity 3.2

Activity 3.2: A Historic View

Note: For a big class, it might be more effective to let students work in two big groups with five sub groups each.

Before doing the activity display a big periodic table in front of the class. (In the absence of a big periodic table, you could tell them prior to the activity to bring a copy of the periodic table).

Inform them that each group will be given a reading material with corresponding questions.

Distribute Students Activity Sheet 3.2a -3.2e,A Historic View, pages 21- 25 Give them time to read and answer the questions in a separate sheet.

After the given time, instruct them to move the paper to the right which is the group next to them. The process will continue until all the sheets are passed on and questions are answered by all the groups.

Note: If your class is big, divide it into ten groups. Since there are only five reading materials, two groups will receive identical reading material.

Provide time for all the groups to finish answering the questions. Since some reading materials have more information than the others, it is expected that some groups will finish ahead of the others. Just tell them to review their work so as not to disturb others who are still working.

Guide students while going through the sheets.

Collect their work and facilitate processing of the information given by their answers to the questions. Teacher Resource Sheet 3 on page 27 provides the answers for the questions.

Ask students to summarize the responses and give a generalization of the said topic.

Materials for Activity 3.3

Teacher Resource Sheet 4- Arrangement of Elements in the Periodic Table, page 29 Student Activity Sheet 3.3.b- Making Sense Of The Elements, page 31

Teacher Resource Sheet 5, Making Sense Of The Elements (Answer Key), page 33 Teacher Resource Sheet 6, Electronic Configuration, page 35

Student Activity Sheet 3.3.a- Blank Periodic Table, page 38 Student Activity Sheet 3.4.a.- Modern Periodic Table, page 39

Activity 3.3: Making Sense Of The Elements

Divide the class into groups of ten.

Distribute Student Activity Sheet 3.3.a, Blank Periodic Table (refer to page 38 ) and other materials.

Instruct them to enlarge the blank periodic table on a manila paper. As this would take time, you may give this as an assignment a day before this activity.

Discuss the Arrangement of Elements in the Periodic Table (refer to Teacher Resource Sheet 4, page 29).

Have a short review on the electronic configuration. Refer to Teacher Resource Sheet 6, Electronic Configuration, page 35.

In this activity use only the first 30 elements.

Distribute Students Activity Sheet 3.3.b – Making Sense Of The Elements page 31 Let them perform the activity.

Note: You may tell the students that they could divide the elements among themselves in the group to make it easier for them to finish the task.

Check their electronic configurations afterwards.

Tell them that they will now act very much like Mendeleev. They will now arrange some elements in the periodic table. Only, in their case, they will do it through the elements' electronic configuration.

Discuss how they will do it by pointing out that the number of electrons in the last orbital will be their basis for the arrangement.

ex. Lithium = 3 = 1s2 _2s1 Last orbital

shell

2s

• The number of electrons in the last orbital, which is also called valence

electron, and its subshell determines the group or family an element belongs. The number of the highest or outermost shell determines an element's period or row.

• For Lithium, valence electron is 1, subshell is s and the outermost shell is 2.

Therefore it falls under Family IA, Period 2.

Ask them now to fill in their enlarged blank periodic table but instruct them to do it in a manner where each box contains the name of the element, symbol and its atomic number as shown below.

Let them post their work. Check their work.

After checking, let them now conclude as to the basis of the arrangement of the elements in the Modern Periodic Table.

(answer: Elements in the periodic table are arranged horizontally by order of increasing atomic number)

In checking their output for this activity refer to the Modern Periodic Table on page 39.

Materials for Activity 3.4

Student Activity Sheet 3.4.a.- Modern Periodic Table, page 39

3

Li

Lithium

Teacher Resource Sheet 7- More About Periodic Table, page41 Student Activity Sheet 3.4.b – Element Chart, page 45

Activity3.4 – Element Chart

Distribute to each group a copy of the Modern Periodic Table. Refer to Student Activity Sheet 3.4.a, Modern Periodic Table, page 39

Give more information on the periodic table of elements by using the Teacher Resource Sheet 7, More About Periodic Table Of Elements, page41.

While discussing let them refer to their periodic table for them to understand more. After the discussion, let them perform the next activity. Refer to Student Activity Sheet 3.4.b , Element Chart, page 45

Collect their work afterwards.

Materials for Activity 3.5

Teacher Resource Sheet 8 – Sample Card, page 46

Teacher Resource Sheet 9- Trends in the Periodic Table, pages 47

Teacher Resource Sheet 10, Periodic Table Magic Square Answer Key, page 50

Activity 3.5 – Periodic Table Trend Game

Prior to the activity, prepare 30 index cards with names and symbols of elements written on it. See attach sample on Teacher Resource Sheet 8, Sample Card, page 46. One element per card.

Discuss trends in periodic properties using Teacher Resource Sheet 8, Trends In Periodic Properties, pages 47.

Group the students in groups of five.

List the trends to be used on the board. For this game, trends should include 1. ionization energy;

2. electronegativity; and 3. atomic radius.

Distribute 30 index cards to each group.

Let one student in the group deal the cards until each student has the same number of cards. Each student should have 6 cards.

The dealer begins the game by throwing the die. The number in the die determines the trend being played. Since only three trends will be used in this game, assign two numbers for every trend. Example, numbers one and two are for electronegativity, three and four are for ionization energy and five and six are for atomic radius.

After the trend for the hand is determined the dealer dealsthe first card. Play continues to the left of the dealer. The card with the highest value for the current trend wins .

Example, if the current trend being played is electronegativity, each player will open their card one at a time and determine the electronegativity of the element indicated in the card. The player having the card with the highest electronegativity wins. The player who takes the hand rolls the die and makes the next deal.

Formative Assessment

Output of each activity will be checked. Answer keys are provided in Teacher Resource Sheet 10, Periodic Table Magic Square Answer Key, page 50

Roundup

With the several activities given, the students should have understood the basicconcepts on order among elements and how they are arranged in the Modern Periodic Table.

4. Check for Understanding of the Topic or Skill

This stage is for teachers to find out how much students have understood before they apply it to other learning experiences.

Background or purpose

The activity below will check if students understood the concepts presented in the previous activities

Strategy

Materials

Student Activity Sheet 4 – Periodic Table Magic Square, page 49

Activity 4 – Periodic Table Magic Square

Let students work individually.

Distribute Student Activity Sheet 4, Periodic Table Magic Square, page 49

Answer the questions in theactivity afterwards. Ask them to check their answers.

Formative Assessment

Entries in thePeriodic Table Magic Square will be checked.

Roundup

Through the correct identification of the magic number, the studentscouldshow that they understood the concepts focused in the topic.

5. Practice and Application

In this stage, students consolidate their learning through independent or guided practice and transfer their learning to new or different situations.

Background or purpose

Elements in the periodic table will be more appreciated if students know their uses. In this stage, they will discover the many uses of the elements.

Strategy

Materials

Student Activity Sheet 5, Element Trading Cards, page 51

Activity 5 – Element Trading Cards

Let the students work by fives.

Provide each group with three blank trading cards and assign three elements. For this activity, just focus on the first thirty elements.

Note: This distribution is for 50 students. In case there are more (or less) 50 students in the classroom, it is now your discretion to adjust the number of elements to be used.

Distribute the Student Activity Sheet 5, Element Trading Cards, page 51

Remind them that they need to use information from the Internet or any chemistry book. Let them present their work to the class.

Tell them to display their cards afterwards. Provide an area for each group. Let the group move from one area to another area where the cards are displayed. Inform them that they will use the information gathered in this activityin the next activity.

Formative Assessment

Check the information given in the element trading cards.

Roundup

Element Trading Cards done by the students widened their knowledge about the elements.

6. Closure

This stage brings the series of lessons to a formal conclusion. Teachers may refocus the objectives and summarize the learning gained. Teachers can also foreshadow the next set of learning experiences and make the relevant links.

Background or purpose

Knowledge about the elements in the periodic table will make students realize their importance: to them, to other people and to the world as a whole. Knowing the

importance of elements will enable the students to imagine what it would be like, if these elements will disappear. The activity that follows will enable them to do so.

Strategy

Journal Writing-is an effective strategy to determine students' understanding of the concepts.

Activity 6 – A Whole New World

Before the activity, display the element trading cards. Provide the students with the following scenario.

From the element trading cards displayed, let each pair choose one and ask them to write a fictionalized “first hand” account of the day the element of their choice disappeared. Present the criterion in assessing their composition. Please refer to page 52.

Let them start using these guide questions.

• Where does the element occur in nature, if at all?

• How is it used by scientists, engineers, artists, doctors, and so on? • Where is its presence crucial?

• How would life be different without it? Would living things even be able to survive? Provide a sample scene.

"The day the Earth lost

IRON

– buildings crumbled, bridges collapsed, blood gradually

lost hemoglobin, etc."

Discuss the information given in the students' composition.

Formative Assessment

Rate their composition using a rubric. Please refer to page 52.

Roundup

With their creative imagination, students should have written a fictionalized “first hand” account of the scenario and consequences if a particular element disappeared. The activity should have made them realize how important each element in the periodic table is.

Teacher Evaluation

(To be completed by the teacher using this Teacher’s Guide) The ways I will evaluate the success of my teaching this unit are: 4.

Student Activity Sheet 3.1

Powerful Pattern

Materials:

ten chips

glue or paste

Procedure:

•

Secure the chips from your teacher.

•

Analyze the information given on the chips.

•

Organize it into some pattern using the grid below.

•

Clue: Since there are ten chips and 16 cells on the grid, there may be cells

that will be empty.

•

Paste it.

•

Answer the given questions.

b. What pattern is shown horizontally?

c. What pattern is shown vertically?

d. Do the given chips give you an idea as to what chips are needed to fill the

vacant cells on the grid?

Teacher Resource Sheet 1

Chips for Powerful Pattern

a

3

f

18

j

21

e

6

b

15

g

30

m

12

o

36

p

48

h

Teacher Resource Sheet 2

Answer Key for Powerful Pattern

Note: Students may have their own pattern.

1. Explain how you came up with the arrangement.

•

Expected answers are based on the given pattern above.

2. What pattern is shown horizontally?

•

Numbers are arranged in interval

s

of three.

3. What trend is shown by the chips which are vertically arranged?

•

Chips are arranged alphabetically.

4. Do the given chips give you an idea as to what chips are needed to fill the

vacant cells on the grid?

•

Yes.

5. If yes, provide the information.

•

First row – 9

•

Second row –

24

•

Third row –

27

, 33

•

Fourth row –

39

, 45

a

3

e

6

m

12

b

15

f

18

21

j

g

30

₃₆

o

h

Student Activity Sheet 3.2.a

A Historic View

(SHEET 1)

The Triad Model

A German scientist, Johan Dobereiner (1780-1849), tried to classify elements into

smaller and simpler subgroups. In 1829, he observed that elements with similar

physical and chemical properties fall into groups of three. He called these related

groups of three elements Triads.

One of these triads included chlorine, bromine and iodine; another consisted of

calcium, strontium, and barium. In each of these triads, the atomic weight of the

intermediate element is approximately the average of the atomic weights of the

other two elements. The density of the element is approximately the average of

the densities of the other two elements.

The problem with these arrangement was that Dobereiner's model became

outdated as new elements were identified. A good model is able to incorporate

newly understood information. Dobereiner's Triad Model was not useful, since

several newly discovered elements did not “fit” into it.

(http://www.genesismission.org/educate)

Questions:

1. Explain how Johan Dobereiner classified elements.

2. Why was the triad model eventually NOT useful?

Student Activity Sheet 3.2.b

A Historic View

(SHEET 2)

The Law of Octaves

In 1864, an English chemist, John Newlands, arranged the known elements in

increasing order of their atomic weights. He noted that chemically similar elements

occurred every eight elements. Lighter sodium was like potassium, and so on

through pairs of elements until fluorine and chlorine, the seventh pair. Since

potassium followed fluorine (the noble gases had not yet been discovered),

Newlands called the repeating pattern the Law of Octaves since the eighth element

resembled the first. His Law of Octaves was based on this observation.

However, there were some deficiencies in Newlands' proposed arrangement.

Several known elements did not fit his pattern. Newlands did not allow the

possibility of the discovery of additional elements at a later date. Further, he did

not question whether all the atomic weight known to that date were correct.

Newlands Law of Octaves was not a good model for explaining the relationship

among the elements. (http://www.genesismission.org/educate)

Questions:

1. What was John Newlands

'

basis when he arranged the elements?

2. Why was his model called the

L

aw of Octaves?

Student Activity Sheet 3.2.c

A Historic View

(SHEET 3)

Mendeleev

In the mid-1800s, most chemists worldwide were convinced that the elements

existed in families that had similar physical and chemical properties. However,

there was no widely accepted chart that explained relationships in chemical

properties among chemical groups. The periodic table, an information organizing

tool that we take for granted today, began as a simple question in the mind of a

Russian scientist, Dmitri I. Mendeleev (1843-1907). What is the relationship of the

elements to one another and to the chemical families to which they belong?

Mendeleev's passion for understanding the families of elements took him into

previously uncharted territory. He felt that the newly understood atomic weight

measurements would have greater significance once scientists clearly understood

the relationship among the elements. Mendeleev wrote his ideas into the chemistry

textbooks from which he taught. In Principles of Chemistry, published in 1869,

Mendeleev introduced a concept he called the Periodic Law that stated:

The properties of the elements are a periodic function of their atomic weights.

He subsequently published several versions of a periodic table of the elements,

including all elements known at that time. How was Mendeleev able to chart th

relationships among the 63 known elements? It all started in a game of cards.

A Game of Cards

In order to understand the properties of the known elements and their relationships

to one another, Mendeleev developed a card game. He wrote out the properties of

each element on a different card and spent a great deal of time arranging and

rearranging them. He was looking for patterns or trends in the data on the cards.

His friends called this game “Patience”.

Mendeleev first arranged all the cards from the lowest to highest atomic mass. The

lightest element known in Mendeleev's time was hydrogen. Its properties were not

like any other known element. So Mendeleev decided to leave it out of his game.

(http://www.genesismission.org/educate)

Questions:

1. What question in Mendeleev's mind formed the basis of today's periodic

table?

2. State Mendeleev's periodic law.

Student Activity Sheet 3.2.d

A Historic View

(SHEET 4)

A Game of Cards

The second lightest element known to Mendeleev at that time was Lithium.

We now know that the second lightest element, between hydrogen and lithium, is

helium. But helium was not discovered on earth until 1895.

So Mendeleev started his game with the element lithium. In order of increasing

mass, Mendeleev thought about the elements beryllium, boron, carbon, nitrogen,

oxygen, and fluorine. These elements were all different in their physical and

chemical properties, thus seeming to belong to different families. Mendeleev put

their cards in a vertical row, with lithium at the top and fluorine at the bottom.

The known element which is more massive after fluorine was sodium. It shared

many physical and chemical properties with lithium. They seemed enough alike to

be classified as belonging to the same family. Thus Mendeleev put sodium's card as

the top of a second column, just to the right of lithium's card.

From there things worked amazingly well. Mendeleev was thinking about the

similar properties of the next elements. Magnesium, following sodium, had physical

and chemical properties similar to beryllium, which followed lithium. In the same

manner, Mendeleev placed aluminum next to boron; silicon next to carbon;

phosphorus next to nitrogen; sulfur next to oxygen; and chlorine next to fluorine.

Mendeleev must have felt great pleasure in how this card game was turning out.

Repeating patterns are called periodic. Mendeleev eventually called this

arrangement the

periodic table of the elements.

(

http://www.genesismission.org/educate)

Questions:

1. Describe how Mendeleev placed his element cards for the first seven elements.

Illustrate it in a tabular form.

2. If Mendeleev found an element with physical or chemical properties that were

similar to another element,

where would he place it? Illustrate it in a tabular

form as well.

Student Activity Sheet 3.2.e

A Historic View

(SHEET 5)

Problem and Predictions

Mendeleev encountered the first problem with his model in the next set of

elements. Potassium headed the third column, since its properties were similar to

those of sodium and lithium. Calcium was next, and it fit well with magnesium and

beryllium.

The next known element was titanium. According to Mendeleev's model, it should

have belonged to the same chemical family as boron and aluminum. But titanium's

properties were similar to those of silicon.

Mendeleev did not give up. He decided to put titanium in the row with carbon and

silicon. He left a gap next to boron and aluminum. He predicted that an unknown

element would some day be found with an atomic mass between 40 (for calcium)

and 48 (for titanium), whose properties would be similar to those of boron and

aluminum.

In fact, in 1879 the element scandium was discovered. Its atomic mass was almost

45, and it had the

properties predicted by Mendeleev.

Mendeleev continued laying down his cards and felt comfortable identifying two

more gaps or “missing” elements in the fourth column rows. His genius is shown in

his ability to recognize the potential for missing data and to use existing data to

predict the properties of these unknown elements. Mendeleev left spaces on his

periodic tables because he did not “force” the known elements to fit any

preconceived pattern. The absence of elements with certain physical and chemical

properties also indicated that not all existing elements have been discovered yet .

Questions:

1. What was the first problem Mendeleev encountered with his model of

arranging the elements?

2. How did he solve his problem? Show it by putting K,Ca and Ti in the proper

spaces in the table below.

Li

Na

Be

Mg

B

Al

C

Si

Li

Na

O

S

F

Cl

3. What element was found in 1879 that filled out the gap between calcium and

titanium?

Teacher Resource Sheet 3

Answer Key for Historic View

1. Explain how Johan Dobereiner classified elements.

He classified elements in small groups that had similar physical properties. Elements were found in groups of three. Therefore, Dobereiner called them triads. The

intermediate element in this threesome had the average atomic weight and density of the other two.

2. Why was the triad model eventually not useful? Newly discovered elements did not “fit” the pattern. 3. Give an example of Triad done by Dobereiner.

Chlorine, bromine and iodine. Another triad; calcium, strontium and barium. 4. What was John Newlands' basis when he arranged the elements?

Newlands arranged elements according to the increasing order of atomic weights. 5. Why was his model called the law of Octaves?

He noted that chemically similar elements occurred in every eighth element. 6. Give two reasons why Newlands' law was not a good model.

Some known elements did not fit into his model and his model did not allow for the possibility of the discovery of additional elements at a later date.

7. What question in Mendeleev's mind formed the basis of today's periodic table?

What is the relationship of the elements to one another and to the chemical families where they belong?

8. State Mendeleev's periodic law.

The properties of the elements are a periodic function of their atomic weights.

9. Why did Mendeleev leave out hydrogen from his game of cards? Its properties were not like any other element.

10. Describe how Mendeleev placed his element card for the first seven elements. Illustrate it in a tabular form.

In vertical columns from lowest (top) to highest (bottom) atomic mass. Li

11. If Mendeleev found an element with physical or chemical properties that were similar to another element,where would he place it? Illustrate it in a tabular form as well.

He would place the newly discovered element next to the other element with similar chemical and physical property.

Li Na

Be Mg

B Al

V Si

N P

O S

F Cl

12. What did Mendeleev call his arrangement of elements? He called it periodic table of elements.

13. What was the first problem Mendeleev encountered with his model of arranging the elements?

Titanium did not fit next to aluminum because it had different properties; titanium had properties closer to silicon.

14. How did he solve his problem? Show it by filling out the third column of the table below. He did not make it fit. Rather, he put the Titaniumnext to Silicon where he thought it belonged and left a gap next to aluminum.

Li Na K

Be Mg Ca

B Al

C Si Ti

N P

O S

F Cl

Teacher Resource Sheet 4

Arrangement of Elements In the Periodic Table

Our modern day periodic table is expanded beyond Mendeleev's initial 63 elements.

Most of the current periodic tables include 108 or 109 elements.

The periodic table is an organized way of displaying information of all known

elements. It is designed to help us predict what an element's physical and chemical

properties are.

The elements within the modern periodic table are arranged from left to right, top

to bottom, in order of increasing atomic number. An element's atomic number is

the number of protons in its nucleus.

Whereas the ordering of the elements is completely determined by their atomic

number, the arrangement into vertical columns, called groups, is determined by a

number of factors. These factors include chemical properties, physical properties,

and the number of electrons thought to exist in the outer shells of the element's

atoms.

The modern periodic table of elements contains 18 groups or families which are

arranged in vertical columns. Elements in a group

(

or vertical column

)

have similar

chemical and physical properties because they have the same number of outer

electrons. Elements in a group are like members of a family-each is different, but

all are related by common characteristics. Each group is represented by either

Roman numerals and the letters A and B or by numerals from one to eighteen. Each

of the table's horizontal rows is called period. Along a period, a gradual change in

chemical properties occurs from one element to another. For example, metallic

properties decrease and nonmetallic properties increase as you go from left to

right across a period. Changes in the properties occur because the number of

protons and electrons increase from left to right across a period or row. The

increase in number of electrons is important because the outer electrons

determine the elements' chemical properties.

The periodic table consists of seven periods. The periods vary in length. The first

period is very short and contains only two elements. The next two periods contain

eight elements each. Periods four and five each have 18 elements. The last period

is not complete yet because new exotic or man-made elements are still being made

in laboratories.

The periodic table is constructed in a way that reflects the distribution of electrons

in the atoms of the elements.

Both the arrangement of the periodic table and electron structure can be used to

predict properties and behavior of any given element. Therefore, you should not be

surprised that the periodic table is related to electron configuration.

1. A complete set of valence electrons (Noble gases – Group VIII-A)

2. Partially filled s and p orbitals (Representative Elements – Group 1A – VIIA) (s

and p orbitals)

3. Partially filled d orbitals (Transition metals) (d block)

4. Partially filled f orbitals (Lanthanides and Actinides) (f block)

Student Activity Sheet 3.3.b

Making Sense of the Element

Procedure:

1. Below is a list of elements and their respective atomic numbers.

2. Provide the symbol and the electronic configuration of each of the element

s

given below.

Element Atomic Number Symbol Electronic configuration

Aluminum 13

Argon 18

Boron 5

Beryllium 4

Carbon 6

Calcium 20

Chlorine 17

Chromium 24

Cobalt 27

Copper 29

Fluorine 9

Hydrogen 1

Helium 2

Iron 26

Lithium 3

Magnesium 12

Manganese 25

Nitrogen 7

Element Atomic Number Symbol Electronic configuration

Nickel 28

Oxygen 8

Phosphorus 15

Potassium 19

Sulfur 16

Silicon 14

Scandium 21

Sodium 11

Titanium 22

Vanadium 23

Teacher Resource Sheet 5

Making Sense of the Elements

(Answer Sheet)

Element Atomic Number Symbol Electronic configuration

Aluminum 13 Al 1s2 _2s2 _2p6 _3s2 _3p1

Argon 18 Ar 1s2 _2s2 _2p6 _3s2 _3p6

Boron 5 B 1s2 _2s2 _2p1

Beryllium 4 Be 1s2 _2s2

Carbon 6 C 1s2 _2s2 _2p2

Calcium 20 Ca 1s2 _2s2 _2p6 _3s2 _3p6 _4s2

Chlorine 17 Cl 1s2 _2s2 _2p6 _3s2 _3p5

Chromium 24 Cr 1s2 _2s2 _2p6 _3s2 _3p6 _4s2 _3d4

Cobalt 27 Co 1s2 _2s2 _2p6 _3s2 _3p6 _4s2 _3d7

Copper 29 Cu 1s2 _2s2 _2p6 _3s2 _3p6 _4s2 _3d9

Fluorine 9 F 1s2 _2s2 _2p5

Hydrogen 1 H 1s1

Helium 2 He 1s2

Iron 26 Fe 1s2 _2s2 _2p6 _3s2 _3p6 _4s2 _3d6

Lithium 3 Li 1s2 _2s1

Magnesium 12 Mg 1s2 _2s2 _2p6 _3s2

Manganese 25 Mn 1s2 _2s2 _2p6 _3s2 _3p6 _4s2 _3d5

Nitrogen 7 N 1s2 _2s2 _2p3

Neon 10 Ne 1s2 _2s2 _2p6

Nickel 28 Ni 1s2 _2s2 _2p6 _3s2 _3p6 _4s2 _3d8

Oxygen 8 O 1s2 _2s2 _2p4

Phosphorus 15 P 1s2 _2s2 _2p6 _3s2 _3p3

Element Atomic Number Symbol Electronic configuration

Sulfur 16 S 1s2 _2s2 _2p6 _3s2 _3p4

Silicon 14 Si 1s2 _2s2 _2p6 _3s2 _3p2

Scandium 21 Sc 1s2 _2s2 _2p6 _3s2 _3p6 _4s2 _3d1

Sodium 11 Na 1s2 _2s2 _2p6 _3s1

Titanium 22 Ti 1s2 _2s2 _2p6 _3s2 _3p6 _4s2 _3d2 Vanadium 23 V 1s2 _2s2 _2p6 _3s2 _3p6 _4s2 _3d3

Teacher Resource Sheet 6

Electronic Configuration

The electron configuration of an atom is a form of notation which shows how the

electrons are distributed among the various atomic orbital and energy levels. The

format consists of a series of numbers, letters and superscripts as shown below:

1s

Here we see the electron configuration for the element helium. This electron

configuration provides us with the following information:



The large number "1" refers to the principle quantum number "n" which stands for

the energy level. It tells us that the electrons of helium occupy the first energy

level of the atom.



The letter "s" stands for the angular momentum quantum number "l". It tells us

that the two electrons of the helium electron occupy an "s" or spherical orbital.



The exponent "2" refers to the total number of electrons in that orbital or

sub-shell. In this case, we know that there are two electrons in the spherical orbital at

the first energy level.

Before we continue, we must review some information that you will need to fill in

electron configurations correctly.

I.

Principle Quantum Number (n) and Sublevels

The number of sublevels that an energy level can contain is equal to the principle

quantum number of that level. So, for example, the second energy level would

have two sublevels, and the third energy level would have three sublevels. The

first sublevel is called an s sublevel. The second sublevel is called a p sublevel. The

third sublevel is called a d sublevel and the fourth sublevel is called an f sublevel.

Although energy levels that are higher than 4 would contain additional sublevels,

these sublevels have not been named because no known atom in its ground state

would have electrons that occupy them.

II. Sublevels and Orbitals

Orbital and Electron Capacity for the Four Named Sublevels

Sublevel Number o Orbitals Maximum number of Electrons

s 1 2

p 3 6

d 5 10

f 7 14

III. Total Number of Orbital and Electrons per Energy Level

An easy way to calculate the number of orbitals found in an energy level is to use

the formula n

. For example, the third energy level (n=3) has a total of 3

, or nine

orbitals. This makes sense because we know that the third energy level would have

3 sublevels; an s sublevel with one orbital, a p sublevel with 3 orbitals and a d

sublevel with 5 orbitals. 1 + 3 + 5 = 9, so the formula n

works!

IV.

Total Number of Electrons per Energy Level

An easy way to calculate the total number of electrons that can be held by a given

energy level is to use the formula 2n

. For example, the fourth energy level (n=4)

can hold 2(4)

= 32 electrons. This makes sense because the fourth energy level

would have four sublevels, one of each of the named types. The s sublevel hold 2

electrons, the p sublevel holds 6 electrons , the d sublevel holds 10 electrons and

the f sublevel holds 14 electrons. 2 + 6 + 10 + 14 = 32, so the formula 2n

works!

We can summarize this information in the table below:

Orbitals and Electron Capacity of the First Four Principle Energy Levels

Principle Energy Level

Type of Sublevel Number of Orbitals per Type

Number of Orbitals per Level

(n2₎

Maximum Number of Electrons (2n2₎

1 S 1 1 2

2

s 1

p 3 4 8

3

s 1

4

s 1

p 3

d 5

f 7

16 32

V.

Order of Filling Sublevels with Electrons

The next thing that you need to recall is the fact that the energy sublevels are

filled in a specific order that is shown by the arrow diagram seen below:

Remember to start at the beginning of each arrow, and then follow it all of the

way to the end, filling in the sublevels that it passes through. In other words,

the order for filling in the sublevels becomes; 1s, 2s, 2p, 3s, 3p, 4s, 3d, 4p, 5s,

4d, 5p, 6s, 4f, 5d, 6p, 7s, 5f, 6d,7p.

Teacher Resource Sheet 7

More About Periodic Table

When you look at the periodic table, you should notice that each box represents a different element, and each box contains vital information about the element, including its name, symbol, atomic number, and atomic mass. Look at the sample box for a description of each of these pieces of information.

The top number is the atomic number. Every element has its own unique atomic number. It tells the number of protons and electrons. Below the name is the element's atomic mass. The atomic mass is the mass in atomic mass units for all possible isotopes of the element. It essentially gives you an estimate of how massive one atom of that element is. The difference of the rounded atomic mass and atomic number gives the number o neutrons. Therefore, in this example; atomic number = 6

atomic weight = 12.011 protons = 30

electrons = 30

neutrons = 12 (atomic mass) – 6 (atomic number) = 6

Classification and General Properties Metals

As you can see, the vast majority of the known elements are metals (left side). Many metals are easily recognized by non-chemists. Common examples are copper, lead, silver and gold. In general, metals have luster, are quite dense, are good conductors of heat and electricity. They tend to be soft, malleable and ductile (meaning that they are easily shaped and can be drawn into fine wires without breaking).

All of these properties are directly related to the fact that solid metals are crystals formed from positive ions surrounded by mobile electrons. This mobility allows it to absorb and reflect light in many wavelengths, giving the metals their typical luster. It also permits electrons to absorb thermal and electrical energy from the environment or neighboring electrons and transferring this to other electrons; in this way, heat and electricity can be conducted throughout the metal. These mobile electrons hold the positive metallic ions so tightly that even when the metal sample is only a few layers thick, as in gold foil, the sample stays intact. So, the density, malleability and ductility of metals are also due to electron mobility.

Alkali Metals

The Alkali (Group IA) metals show a closer relationship in their properties than do any other family of elements in the periodic table. Alkali metals are so chemically reactive that they are never found as free element in nature. All these metals react spontaneously with gases in the air, so they must be kept immersed i oil in the storeroom. They are so soft that they can be cut with an ordinary table knife, revealing a very “buttery”, silvery metal surface that immediately turns

6

C

Carbon

dull as it reacts with water vapor and oxygen in the air. The chemical reactivity of alkali metals increases as the atomic number increases.

Their reactions with halogens, elements in Group VIIA, are especially spectacular because some of them emit both light and heat energy. They react with other nonmetals, albeit more slowly, forming compounds that are very stable. They also react with acids, forming hydrogen gas and salts; with water they form hydrogen gas and metallic hydroxides, which are sometimes called bases They react with hydrogen to form metallic hydrides, which form strong bases in water. In all these reactions, the metals form ionic compounds, in which each metal atom loses one electron to form positively-charged ion or cation.

Alkali Earth Metals

Alkaline Earth (Group IIA) metals also exhibit the typical metal characteristics of high density, metallic luster and electrical and thermal conductivity. They form compounds by losing, or in the case of beryllium, sharing two electrons per atom. These atoms hold their electrons more tightly than alkali metals. They are, therefore, smaller than and not so chemically reactive as the neighboring alkali metals. They do not require special storage because the surface of these metals reacts with air, forming a tightly adhering layer that protects the metals and prevents additional reactions. None of them is found naturally as a free element.

Transition Metals

The transition or heavy (Group IIIB-IIB) metals have most of the usual properties of metals. Their densities, which are greater than the Group IA and IIA metals, increase and then decrease across a period. The transition metals are also called heavy metals because their atoms are relatively small and their large number of protons and neutrons give them relatively large masses. There is a great variance in the chemical reactivity of transition metals. All the transition elements react with halogens and most react with sulfur and oxygen. The elements fro scandium through copper form compounds that are soluble in water.

One of the main uses for transition metals is the formation of alloys-mixtures of metals-to produce tools and construction materials for specific uses. For example, structural steel alloys, which are used in automobiles and building construction, can contain as much as 95% iron. There are also carbon and at least six different high-alloy steels, some of which contain manganese, chromium, nickel, tungsten, molybdenum and cobalt: all are transition metals.

Some of the transition metals exhibit colored luster and some of them are more brittle than the Group IA and IIA metals. Whereas the compounds of the Group IA and IIA metals are white, any of the transition metal compounds are brightly colored. Many heavy metal compounds, such as those of mercury, cadmium, zinc, chromium and copper, are poisonous.

Rare Earth Metals

a. Lanthanides

The fourteen lanthanide elements follow lanthanum (La) in the periodic table. They generally occur together in a phosphate mineral such as monazite. They are similar in chemical an physical properties that they are difficult to separate from each other. Promethium (Pm) is unstable, and is not found in nature.

b. Actinides

The fourteen actinides follow actinium (Ac) in the periodic table. They are unstable, and most do not occur in nature. Less is known about these elements than about any other family, since some of them have only been produced in tiny quantities. Uranium (U) is the most well-known naturally occurring member of this group of elements.

Other metals include heavier elements of Groups IIIA, IVA, and VA. They form a staircase inside the periodic table. The metals in Group IIIA are aluminum (Al), gallium (Ga), indium (In), and thallium (Tl). The metals in Group IVA are in tin (Sn) and lead (Pb), and the only metal in Group VA is bismuth (Bi). As atomic number decreases within each group, their metallic character gets weaker.

Aluminum is the only true metal in Group IIIA. Aluminum ores are found in great abundance in the Earth's crust.

Metalloids

The metalloids include boron(B), silicon (Si) and germanium (Ge), arsenic (As) and antimony (Sb), tellurium (Te) and polonium (Po). Note that are arranged in stair steps between the metals and nonmetals.

Metalloids have some of the properties of metals and nonmetals-and each metalloid has its own unique mixture. A few are shiny like metals, but do not really have a metallic luster. Some metalloids have very high melting and boiling points; others do not. Others conduct electricity-but their electrons are mobile in only certain directions, so they are called semi-conductors. This makes them useful in designing transistors and other solid state electronic components.

Nonmetals

The nonmetallic elements are in the upper right portion of the Periodic Table. At room

temperature and pressure, many of them exist as gases, but one is a liquid. Others are either the hardest or the softest of solids. The nonmetals have few chemical properties in common. They range from fluorine, the most active nonmetal, to the most nonreactive of the elements, the noble gases.

Oxides of sulfur and nitrogen have been identified as atmospheric pollutants. Nonmetallic compounds also include salts as well as many acids and bases. Many of these salts are found in soil or dissolved in ocean water.

Many of the nonmetals are colored, including yellow sulfur, red and yellow-green fluorine, pale yellow chlorine, red- brown bromine, and violet black iodine. Others like oxygen, nitrogen, and the noble gases are colorless. Only sulfur is found as a free element in nature.

Some of the nonmetals are molecular, such as the diatomic halogens, nitrogen, and oxygen; phosphorus forms molecules of four atoms and sulfur is found in rings of eight atoms. The noble gases exist as monoatomic gases. On the other hand, any sample of carbon, whether it be the graphite in your pencil lead or a diamond, is one large molecule of carbon atoms.

If metal atoms are closely packed like stacked building materials, leading to high densities, then the low density of nonmetals is like the same building materials widely distributed with open spaces between them in the constructed building. Electrons in the crystalline structures of nonmetallic solids are tightly held in chemical bonds; so, nonmetals are notably good electrical and thermal insulators.

Halogens

The halogens are the gases in Group VIIA of the periodic table. Their name indicates that they are self-formers. This is appropriate since they react easily with other elements, especially the alkali and alkaline earth elements in the left columns of the periodic table. They are all considered highly reactive elements.

Chlorine (Cl) is one of the halogens. It is a highly poisonous yellow and green-colored gas. It combines easily with an explosive alkali metal called sodium (Na) to form a compound called sodium chloride. The compound's chemical formula is NaCl, and it goes by the common name of tale salt.

The noble gases were unknown in Mendeleeve's time. The lightest and most stable of these gases, helium, was discovered from its bright yellow solar spectral line in 1868. The existence of helium on Earth was not discovered until 1895. The noble gases Group 0 in the periodic table. These elements are termed noble because they do not interact with other elements to form compounds. Another way to say this is that they are inert. Their atoms do not even interact with each other, so they exist as mono atomic gases.

Hydrogen

Chemists are not in agreement about the placement of hydrogen on the periodic table. In the periodic table, hydrogen is shown as nonmetal, but placed above Group IA metals, because it also exhibits some chemical properties similar to those metals. It exists in the free state as diatomic molecules and it reacts with active metals in much the same manner as the halogens. But it also found bonded to other nonmetals in organic compounds.

Hydrogen is the most abundant element in the universe. It is estimated that ninety percent of the atoms in the universe are hydrogen atoms. The sun and other stars appear to be composed largely of hydrogen, as do the gases found in interstellar space.

Hydrogen is a component of more compounds than any other element and make up 11% of the mass of water, its most abundant compound. It is the principal energy source in the Sun's high temperature nuclear fusion reaction.

Four Groups Of Elements

1. Group A (Representative Elements) • groups IA, IIA, IIIA-VIIIA

2. Group B (Transition Elements) • Groups IIIB – IIB

3. Inner Transition Elements – (Lower Block of transition metals) 4. Noble Gases

Sourcee: http://www.citycollegiate.com/periodictable.htm http://web.buddyproject.org/web017

Element Symbol Atomic

Number Atomic Mass ProtonsNo. of No. of Neutrons No. of Electrons Metal, Non-Metal or

Metalloid

Chemical State (solid, liquid or gas)

Characteristics (color, odor, etc.)

Interesting Facts

Oxygen Hydrogen

Carbon Aluminum Magnesium

Teacher Resource Sheet 8

Sample Card

C

Teacher Resource Sheet 9

Trends In Periodic Properties

The properties of the elements exhibit trends. These trends can be predicted using the periodic table and can be explained and understood by analyzing the electron

configurations of the elements. Elements tend to gain or lose valence electrons to achieve stable octet formation. Stable octets are seen in the inert gases, or noble gases, of Group VII of the periodic table. In addition to this activity, there are two other important trends. First, electrons are added one at a time moving from left to right across a period. As this happens, the electrons o the outermost shell experience increasingly strong attraction, so the electrons become closer to the nucleus and more tightly bound to it. Second, moving down a column in the periodic table, the outermost electrons become less tightly bound to the nucleus.

This happens because the number of filled principal energy levels (which shield the outermost electrons from attraction to the nucleus) increases downward within each group. These trends explain the periodicity observed in the elemental properties of atomic radius, ionization energy, electron affinity, and electronegativity.

Atomic Radius

The atomic radius of an element is half of the distance between the centers of two atoms of the element that are just touching each other. Generally, the atomic radius decreases across a period from left to right and increases down a given group. The atoms with the largest atomic radii are located in Group I and at the bottom of groups.

Moving from left to right across a period, electrons are added one at a time to the outer energy shell. Electrons within a shell cannot shield each other from the attraction to protons. Since the number of protons is also increasing, the effective nuclear charge increases across a period. This causes the atomic radius to decrease.

Moving down a group in the periodic table, the number of electron shells increases, but the number of valence of electrons remains the same. The outermost electrons in a group are exposed to the same effective nuclear charge, but electrons are found farther from the nucleus as the number of filled energy shells increases. Therefore, the atomic radii increases.

Ionization Energy

The ionization energy, or ionization potential, is the energy required to completely remove from a gaseous atom or iron. The closer and more tightly bound an electron is to the nucleus, the more difficult it will be to remove, and the higher its ionization energy will be. The first ionization energy is the energy required to remove one electron from the parent atom. The second ionization energy is the energy required to remove a second valence electron from the univalent electron ion, and so on. Ionization energies increases moving from let to right across a period (decreasing atomic radius). Ionization energy decreases moving down a group (increasing atomic radius. Group I elements have low ionization energy because the loss of an electron forms a stable octet.

Electronegativity

(i.e, low electronegativity) element is cesium; an example of a highly electronegative element is fluorine.

Summary of Periodic Table Trends

Atomic Radius

I n c r e a s e

Decrease

Electronegativity

D e c r e a s e

D e c r e a s e

Increase

Increase

Student Activity Sheet 4

Periodic Table Magic Square

Procedure:

Put the number of the definition from the list below into the square with the

appropriate term. Arrange the squares so that the sum of the numbers in all

the columns and rows add up to the same number. Your answers are correct if

the sum of all rows and columns add up to the Magic Number.

Ionization Energy _____ Atomic number _____ Atomic radius _____ Magic Number _____ Families _____ Valence _____ Neutron _____ Magic Number _____ Electron _____ Mass number _____ Proton _____ Magic Number _____ Magic Number _____ Magic Number _____ Magic Number _____ Magic Number _____

1. periodic trend that increases from the left to right of the periodic

table.

2. Vertical columns on the periodic table

3. number of protons in an element

4. the electrons in the outermost energy level

5. periodic trend that also increases as elements move from top to bottom

6. negative subatomic particle