Section 2.2 Notes
Periodic Table
(Text Pages 48 – 59)
Key Terms:
Periodic Table
Atomic number
Atomic Mass
Mass Number (notes)
Metals
Non-metals
Metalloids
Period
Chemical Family
Alkali metals
Alkaline Earth Metals
Halogens
Noble Gases
Learning Objectives:
Know what the periodic table is and how the work of Demitri Mendeleev contributed to its development.
Know the difference between atomic number and atomic mass.
Be able to determine the number of protons, electrons, and neutrons in an atom for any element. Be able to locate and list the properties of elements belonging to the following groups on the
periodic table:
(i) metals (ii) non-metals (iii) metalloids (iv) transition metals. Know what periods and families are on the periodic table
Be able to identify and list the properties of the following chemical families:
(i) alkali metals (ii) alkaline earth metals (iii) halogens (iv) noble gases _____________________________________________________________________________________
Portfolio Items:
Worksheet #7 – “Organizing Elements - Text Questions:
Worksheet #8 – Using the Periodic Table Pg 59: 2, 3, 5, 8, 10 – 12, 17-22, 25 Worksheet #9 – Types of Elements
_____________________________________________________________________________________
What is the Periodic Table?
Periodic Table: a chart that organizes all of the elements based on their properties.
The periodic table contains information about the different elements that make up all the solids, liquids, and gases in the known universe.
In the 1800’s, chemists were aware of many different elements. However despite the efforts of
many scientists, they had no effective way to organize them!
Mendeleev and the Periodic Table
The elements remained disorganized until the 1860’s when a chemist named Demitri Mendeleev
developed an organization system that is still in use today.
Mendeleev’s Important Contributions:
1. Arranged the known elements based on their physical and chemical properties.
o Useful because elements that are similar are close together on the table.
2. He left empty spaces in his periodic table and predicted that new elements would be found to fill
these spaces.
o As he put his table together, he noticed that there seemed to be some elements missing!
o This was very important because it gave other chemists elements to look for and led to the discovery of new elements.
Using the Periodic Table
Each box on the periodic table contains information about one element. It tells us important
information about the atoms of that element.
Example: Iron Atomic Number:
Equals the number of protons (p+) in an atom of this
element.
Equals the number of electrons (e-) in an atom of this
element.
**Atoms must have a net neutral charge. This means the
# of protons (+) must equal the # of electrons (-)!
Chemical Symbol:
Identifies the element using letters.
Atomic Mass:
The average mass of an atom of this element .
Mass Number: the rounded atomic mass. It tells you combined number of protons and neutrons.
Ex: Iron has a mass number of 56 because atomic mass of 55.8 rounds up! greater than or equal to 0.5 rounds up! (23.5 24 ) less than 0.5 rounds down! (23.4 23 )
Summary
# of protons = atomic number
# of electrons = atomic number (same as protons for an atom!)
# of neutrons = mass number – atomic number (see example below)
Calculating # of Neutrons Example (Iron)
Step 1: Find the mass number by rounding the atomic mass: Iron’s atomic mass is 55.8 so the mass number is 56!
Step 2: Subtract the atomic number from the mass number. This gives you the number of neutrons:
# of neutrons = Mass # - Atomic # # of neutrons = 56 – 26
Example #2: Sulfur
Atomic # = __________ # of p+ = ___________ Atomic mass = __________ # of e- = ___________ Mass # = __________ # of n0 = ___________
**Calculating Neutrons:
_____________________________________________________________________________________
Example #3: ____________________ ???
*We need to figure out the element based on the information given. Then we can fill the other blanks!
Atomic # = 12 # of p+ = ___________
Atomic mass = __________ # of e- = ___________ Mass # = __________ # of n0 = ___________
**Calculating Neutrons:
_____________________________________________________________________________________
Example #4: ___________________ ???
Atomic # = __________ # of p+ = ___________ Atomic mass = __________ # of e- = 37
Mass # = __________ # of n0 = 49
**Which information helps us the most?
Types of Elements
Mendeleev identified three main types of elements on the periodic table: 1. Metals
2. Non-Metals 3. Metalloids
The image below shows where to identify each type of element on the periodic table. You will need to remember this!
Properties of Metals, Non-metals and Metalloids
These three main types of elements are identifiable by their different properties:
Metals Non-metals Metalloids
- all solid (except Mercury, liquid)
- Shiny
- malleable
- ductile
- conduct electricity
- conduct heat
- solids, liquids and gases
- not shiny (dull)
- not malleable (brittle)
- not ductile
- poor conductors of electricity
- poor conductors of heat
Not all have the same properties! Some are
more metal, others are more non-metal.
- all solids
- shiny
- not malleable (brittle)
- not ductile
- may conduct electricity
- poor heat conductors
Grouping the Elements: Periods and Families
Recall that Mendeleev organized the elements based on their properties, with elements that were similar being closer together on the periodic table.
As he organized them he noticed patterns in their properties. These patterns helped him structure the periodic table into Periods and Families (also called groups)
Periods: horizontal rows on the periodic table. They are numbered 1 to 7.
Families: Also called groups. They are groups of elements arranged in vertical columns numbered 1 to 18. Elements in the same group share similar properties.
On your copy of the periodic table: (You can use page 50 of your text for help) - Label the periods from 1 to 7
- Label the groups from 1 to 18
- Label each family that we learn about in our notes.
Important Chemical Families
You must be able to identify each of these families on the periodic table.
You must be familiar with the properties described in your notes for each family.
Alkali Metals (Group 1)
-
React strongly with both oxygen and water.
-
Very soft metals. Can be cut with a knife.
-
Low melting points
for metals (below 200
OC)
-
Reactivity increases down the family (K is more reactive than Na)
Alkaline Earth Metals (Group 2)
-
Less reactive
than alkali metals
-
Produce bright coloured flames when burned in air. (Used in fireworks!)
Examples: Magnesium (Mg) and Calcium (Ca)
Transition Metals
(Groups 3-12)
-
Not technically a chemical family because they are spread out over several groups.
-
Found in the centre of the periodic table
-
Grouped together because they all have complex arrangements of electrons which
allows them to react in special ways.
-
Some similarities exist in each column (Ex: copper, silver, and gold all resist corrosion.)
Halogens (Column 17)
-
Highly reactive non-metals
-
Only family that contains each state at room temperature:
o
Gases: F and Cl
o
Liquid: Br
o
Solid: I
-
Reactivity increases going UP the family. (Fluorine is the most reactive)
Noble Gases (Column 18)
-
Most stable elements (means they do not react)
-
They are all naturally colourless and odourless gases at room temperature
-
They glow different colours when electricity is passed through them.
Worksheet #7
Organizing Elements
Organizing “Elements” Activity
Draw your completed organization system in the space below. Sketch each item! Arrange them in whatever way makes sense to you!
For colours you can just write the name of the colour!
Predict what your missing items should be! Clearly circle these!
Worksheet #8
Using the Periodic Table
Complete the table below. Show your calculations for the neutrons (where needed)
Element Name Chemical
Symbol Atomic #
Atomic
Mass Mass # # of p
+
# of e- # of n 0
1. K 19 39
2. 18 22
3. Ra 226
4. 47 61
5. 201 80
6.
7. Hydrogen 1
8. 58.93
9. Nitrogen
Worksheet #9
Types of Elements
1. List three examples of elements that are ductile
2. List three examples of elements that may be shiny but poor conductors of heat.
3. List three examples of elements that are brittle and dull.
4. Complete a Venn diagram in the space below for metals, non-metals and metalloids. (See example on board). Include all terms listed below in the proper location(s)
Shiny Dull Brittle Malleable
Ductile Conducts heat Conducts electricity Not Ductile
5) Table with period, group, family name, property *For element type, write metal, non-metal, or metalloid
Element Name Symbol Element Type Period # Group # Family Name (If Applicable
Helium
6 10
2 Alkali Metals
Tungsten
Neon
4 8
5 17
4 2
2 Halogens
3 Noble Gases
Silicon
Oxygen
6) Identify which family (including transition metals) each of the following belongs to based on the description provided:
I. Are used in fireworks because they produce bright flames _______________________
II. These elements do not react _______________________
III. Make up the central part of the periodic table _______________________
IV. React violently with water _______________________
