1. Periodic table.ppt

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Chemistry

Periodic Table of Elements

Ch.5.1

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• Dmitri Mendeleev, father of the periodic table.

• Organized based on

element’s CHEMICAL properties.

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Periodic Groups Ch.5.2

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Alkali Metals

• 1st Group, not including

hydrogen.

• 1 Valence electron.

• Very reactive metals, always combined with something else in nature • Soft enough to cut with a

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Alkaline Earth Metals

• Second Group:

• 2 Valence electrons

• Also reactive metals that are always combined with

nonmetals in nature.

• Several of these elements are important mineral

nutrients (such as Mg and Ca

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Transition Metals

• Elements in groups 3-12 • Less reactive

• Harder metals

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Groups 13 - 18

Representative Elements

These groups can contain metals, nonmetals, and metalloids

And have members

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Group 13—The Boron Family

• All are metals except

boron, which is a brittle, black metalloid.

• Cookware made with boron can be moved directly from the

refrigerator into the

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Group 13—The Boron Family

• Aluminum is used to make soft-drink cans, cookware, siding for homes, and

baseball bats.

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The 14th Group

• Carbon is the fourth most abundant element in the

known universe but not nearly as common on the earth. Diamonds, graphite, coal, CO2, methane, etc...In small amounts it is an excellent hardener for iron, yielding the various steel alloys upon which so much of modern construction depends. All living things have it...radiocarbon dating.

• Silicon is 2nd in abundance in the earth's crust

(makes up 25% of it). The most common

compound of silicon, SiO2, is THE most abundant

chemical compound in the earth's crust. We know it better as common beach sand. Silicon is a

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Group 15—The Nitrogen Group

• Nitrogen and Phosphorus are

elements part of the biological materials that store genetic

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Group 15—The Nitrogen Group

• The element phosphorus comes in two forms—white and red.

• White phosphorus is so active it can’t be exposed to oxygen in the air or it will burst into flames.

• The heads of matches contain the less active red phosphorus, which ignites from the heat produced by friction when the match is

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Group 15—The Nitrogen Group

• Phosphorous compounds are essential ingredients for healthy teeth and

bones.

• Plants also need

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Group 16—The Oxygen Family

• The first two members of Group 16, oxygen and sulfur, are essential for life.

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Group 16—The Oxygen Family

• About 20 percent of Earth’s atmosphere is the oxygen you breathe.

• Oxygen also is required for

combustion to occur.

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Oxygen

• Discovered in 1773

• Very reactive non-metal.

• 3rd most abundant element in the universe by mass (after H and He).

• 1st most abundant element in the Earth’s crust.

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Group 16

• _{Sulfur is a solid, yellow nonmetal.}

• Large amounts of sulfur are used to manufacture sulfuric acid, one of the most commonly used

chemicals in the world.

•_• _{It is used in the}

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Group 16

• Selenium conducts electricity when exposed to light, so it is used in solar cells, light

meters, and photographic materials...

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Section Check

Question 1

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Section Check

Answer

Halogen means “salt-former.” All the

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Group 17—The Halogen Group

• _{All are very reactive nonmetals except for} astatine, which is a radioactive metalloid.

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• _{These elements are} called halogens, which means “salt-former.”

• All of the halogens

form salts with sodium and with the other

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3 0

The Noble Gases

• Elements in group 18 • VERY unreactive,

monatomic gases

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InnerTransition Metals

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Group 18—The Noble Gases

• Helium is less

dense than air, so it’s great for all kinds of

balloons.

Representative Elements 2

2

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Uses for the Noble Gases

• The “neon” lights you see in

advertising signs can contain any of the noble gases, not just neon.

Representative Elements 2

2

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Uses for the Noble Gases

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• Each noble gas

produces a unique color.

• Helium glows yellow,

• Neon glows red-orange,

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Uses for the Noble Gases

• Argon, the most abundant of the noble gases on Earth, was first found in 1894.

• Krypton is used with nitrogen in ordinary lightbulbs because these gases keep the glowing filament from burning out.

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Uses for the Noble Gases

• At the bottom of the group is radon, a

radioactive gas produced naturally as uranium

decays in rocks and soil. • If radon seeps into a home,

the gas can be harmful because it continues to emit radiation.

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3 3 8 8

Periodic Properties

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3 3 9 9

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4 4 0 0

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ATOMIC RADII TREND_{ATOMIC RADII TREND}

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In general, the atomic radii increases _{In general, the atomic radii increases}

down a group and decrease across a

period.

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4 4 1 1

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The trend to smaller atoms across a The trend to smaller atoms across a

period is caused by the increasing positive

charge of the nucleus.

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Radii increase down a group because of Radii increase down a group because of increasing energy sublevels. Ex.

increasing energy sublevels. Ex.

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4 4 2 2

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Why does Gallium have a smaller radii Why does Gallium have a smaller radii than Aluminum?

than Aluminum?

 because of the d-block elements. The 3rd _{because of the d-block elements. The 3rd} main energy level is filled so it has a higher main energy level is filled so it has a higher

nuclear charge than aluminum. nuclear charge than aluminum.

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4 4 3 3

Ionization Energy Trends

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4 4 4 4

Ionization Energy

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An electron can be removed from an atom An electron can be removed from an atom if enough energy is supplied.

if enough energy is supplied.

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Let A = any atomLet A = any atom

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A + energy --> AA + energy --> A++ + e_{+ e}-

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An An ion_ion is formed through the process of is formed through the process of

ionization

ionization. .

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Ion

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An atom or group of bonded atoms that An atom or group of bonded atoms that has a positive or negative charge.

has a positive or negative charge.

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Ionization is the formation of an ionIonization is the formation of an ion

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Ionization energy is energy required to Ionization energy is energy required to

remove one electron from a neutral atom

of an element.

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4 4 7 7

Ionization Energy, IE

 It takes different amounts of energy to remove electrons It takes different amounts of energy to remove electrons from certain atoms.

from certain atoms.

 Energy is measured in kJ/mol (kilojoules). Energy is measured in kJ/mol (kilojoules).

 In general, ionization energies increase across In general, ionization energies increase across

each period (due to the increased nuclear charge

that affects radii) and decrease down the groups

(electrons in highest energy levels are further

from nucleus and shielded by other electrons).

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5 5 0 0

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It’s also possible to remove electrons from It’s also possible to remove electrons from positive ions.

positive ions.

 second ionization energy IE_{second ionization energy IE}22

 third ionization energy IE_{third ionization energy IE}33

 _{and so on}_{and so on}

 After each electron is removed, there is a _{After each electron is removed, there is a} stronger nuclear charge on the left over stronger nuclear charge on the left over

electrons, therefore... electrons, therefore...

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5 5 1 1

Electron Affinity Trends

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5 5 2 2

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5 5 3 3

Electron Affinity

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Neutral atoms can acquire electrons. The Neutral atoms can acquire electrons. The electron affinity is the energy change that

electron affinity is the energy change that

occurs when an electron is acquired. Energy

is usually released when this happens.

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A + e

--

--> A

--

+ energy

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Sometime atoms are forced to acquire an eSometime atoms are forced to acquire an e--. _.

A + e

--

+ energy --> A

-

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The electron affinity #’s are negative The electron affinity #’s are negative because energy is being given off.

because energy is being given off.

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Money into a bank = positive, take money Money into a bank = positive, take money out = negative.

out = negative.

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Group 17 have highest electron affinities.Group 17 have highest electron affinities.

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Large negative numberLarge negative number

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Group 14 and 15Group 14 and 15

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Adding an electron to a group 14 gives a Adding an electron to a group 14 gives a half filled p sublevel.

half filled p sublevel.

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This occurs much more easily than forcing This occurs much more easily than forcing an electron to pair with another electron in

an electron to pair with another electron in

an orbital of the already half filled p

sublevel of a group 15

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5 5 7 7

Ionic Radii Trends

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Ionic Radii Trends

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5 5 9 9

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Positive ions are called Positive ions are called cations. _cations.

 _{formation leaves a smaller radius}_{formation leaves a smaller radius}

 Smaller cloud and more pull from nucleus on _{Smaller cloud and more pull from nucleus on} each electron

each electron

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Negative ions are called Negative ions are called anions. _anions.

 formation leaves a larger radius. _{formation leaves a larger radius.}

 electrons are not as pulled toward the nucleus as electrons are not as pulled toward the nucleus as much anymore and they exert greater repulsion

much anymore and they exert greater repulsion

from there being more negative charges.

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6 6 0 0

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Metals tend to form cationsMetals tend to form cations

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Cationic radii decrease across a period Cationic radii decrease across a period because of increased nuclear charge

because of increased nuclear charge

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Nonmetals tend to form anionsNonmetals tend to form anions

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Anionic radii decrease across each period Anionic radii decrease across each period for the elements in group 15-18 for same

for the elements in group 15-18 for same

reason

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Radii increases down a group just as for Radii increases down a group just as for non-ions

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Valence electrons

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Chemical compounds form because Chemical compounds form because electrons are lost, gained, or shared

electrons are lost, gained, or shared

between atoms.

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Electrons in the highest energy levels are Electrons in the highest energy levels are most subject to the influence of nearby

most subject to the influence of nearby

atoms

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These available electrons are ValenceThese available electrons are Valence

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Usually lost from incompletely filled main Usually lost from incompletely filled main energy levels

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6 6 2 2

P block

group 13-18

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Have valence electrons equal to the group Have valence electrons equal to the group number minus 10

number minus 10

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These are the s and p sublevel electrons These are the s and p sublevel electrons which can both be involved in compound

which can both be involved in compound

formation

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Electronegativity Trends

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6 6 7 7

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Electronegativity measures the ability of Electronegativity measures the ability of

an atom in a chemical compound to attract

electrons.

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Fluorine is most electronegative and Fluorine is most electronegative and arbitrarily given a value of 4.0

arbitrarily given a value of 4.0

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General rules-General

rules- Increase across period_{Increase across period}

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7 7 1 1

D block

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Atomic radii decrease across periodAtomic radii decrease across period

 Less decrease in radius because they are _{Less decrease in radius because they are} inner sublevel and shield outer electrons inner sublevel and shield outer electrons

 After awhile more electrons added repel each _{After awhile more electrons added repel each} other and make radius larger

other and make radius larger

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Ionization energy increase across period Ionization energy increase across period and contrary to main group increase down

and contrary to main group increase down

each period

 Lose s shell before d so normally 2+ ions_{Lose s shell before d so normally 2+ ions}

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Low electronegativities which increase as Low electronegativities which increase as radii decrease

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7 7 2 2

F Block

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Lanthanum -> Hafnium big change in Lanthanum -> Hafnium big change in

atomic number; that why Zr bigger than Hf

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Ionization energies increase across periodIonization energies increase across period

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8 8 4 4

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Why are there only two elements for the Why are there only two elements for the period of the table? H and He?

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8 8 6 6

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Only two electrons can occupy the first energy level in an atom. The third

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Relationship of the Periodic Table to Atomic Structure

• Lithium starts a new period at the far left in the table and becomes the first element in a group.

• A group, sometimes also called a family, consists of the elements in a vertical

column.

Periodic Table: Basic Concepts

Periodic Table: Basic Concepts Periodic Table: Basic Concepts

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8 8 9 9

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Each has one more electron than the element that preceded it.

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Eight electrons are added to Period 2 from lithium to neon, so eight electrons must be the number that can occupy the second

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9 9 1 1

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For the main group elements, the group number is related to the number of

valence electrons.

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The main group elements are those in Groups 1, 2, 13, 14, 15, 16, 17, and 18.

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For elements in Groups 1 and 2, the group number equals the number of valence

electrons.

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For elements in Groups 13, 14, 15, 16, 17, and 18, the second digit in the group

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9 9 3 3

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Because elements in the same group have the same number of valence

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9 9 4 4

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9 9 6 6

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The color coding in the periodic table on

pages 92 and 93 identifies which elements are metals (blue), nonmetals (yellow), and metalloids (green).

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Elements are classified as metals,

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Nonmetals

• Although the majority of the elements in the periodic table are metals, many nonmetals are abundant in nature

• The nonmetals oxygen and

nitrogen make up 99 percent of Earth’s

atmosphere.

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Nonmetals

• Carbon, another nonmetal, is found in more compounds than all the other elements

combined.

• The many

compounds of

carbon, nitrogen, and oxygen are important in a wide variety of applications.

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9 9 9 9

Properties of Metals and Nonmetals

Topic 5

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1 1 0 0 0 0 Metalloids

• _Metalloidshave some chemical and physical properties of metals and other properties of nonmetals.

• In the periodic table, the metalloids lie along the border between metals and nonmetals.

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1 1 0 0 1 1

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Some metalloids such as silicon,

germanium (Ge), and arsenic (As) are semiconductors.

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1 1 0 0 2 2

Semiconductors and Their Uses

• Your television, computer, handheld electronic games, and calculator are

electrical devices that depend on silicon

semiconductors.

• All have miniature electrical circuits that use silicon’s properties as a semiconductor.

Topic 5

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