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Unit 3 Unit 3 Periodic Table Periodic Table and Valence and Valence electrons electrons

Unit 3 Periodic Table and Valence electrons. Modern Periodic Table Elements are arranged by increasing atomic number. Elements are arranged by increasing

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Page 1: Unit 3 Periodic Table and Valence electrons. Modern Periodic Table Elements are arranged by increasing atomic number. Elements are arranged by increasing

Unit 3Unit 3Periodic TablePeriodic Table

and Valence electronsand Valence electrons

Page 2: Unit 3 Periodic Table and Valence electrons. Modern Periodic Table Elements are arranged by increasing atomic number. Elements are arranged by increasing

Modern Periodic TableModern Periodic Table Elements are arranged by increasing Elements are arranged by increasing

atomic number.atomic number.– Recall that atomic number gives the Recall that atomic number gives the

number of protons in the nucleus of an number of protons in the nucleus of an atom.atom.

Page 3: Unit 3 Periodic Table and Valence electrons. Modern Periodic Table Elements are arranged by increasing atomic number. Elements are arranged by increasing

PeriodsPeriods Horizontal rows on the periodic table Horizontal rows on the periodic table

are called periods.are called periods.

Elements in the same period have Elements in the same period have the same number of the same number of energy levelsenergy levels..

Elements in the same period share Elements in the same period share NONO similar chemical properties. similar chemical properties.

Page 4: Unit 3 Periodic Table and Valence electrons. Modern Periodic Table Elements are arranged by increasing atomic number. Elements are arranged by increasing

Groups / FamiliesGroups / Families Vertical columns on the periodic Table are Vertical columns on the periodic Table are

called groups.called groups.

Groups are numbered 1-18Groups are numbered 1-18

Elements in the same group have the Elements in the same group have the same same chemicalchemical properties because they properties because they have the same number of have the same number of valencevalence electrons.electrons.

Valence Electrons – electrons in the Valence Electrons – electrons in the highest energy level s and p orbitals only.highest energy level s and p orbitals only.– They participate in bonding and ion formationThey participate in bonding and ion formation

Some groups have special names.Some groups have special names.

Page 5: Unit 3 Periodic Table and Valence electrons. Modern Periodic Table Elements are arranged by increasing atomic number. Elements are arranged by increasing

Groups/FamiliesGroups/Families

Page 6: Unit 3 Periodic Table and Valence electrons. Modern Periodic Table Elements are arranged by increasing atomic number. Elements are arranged by increasing

Group 1 MetalsGroup 1 Metals

Known as Known as Alkali MetalsAlkali Metals Most Most activeactive metals on periodic table metals on periodic table React violently with water, and React violently with water, and

become become moremore reactive down the reactive down the groupgroup

Only have 1 valence electron Only have 1 valence electron (because they all end in s(because they all end in s11))

They all form ions with a They all form ions with a +1+1 charge. charge.

Page 7: Unit 3 Periodic Table and Valence electrons. Modern Periodic Table Elements are arranged by increasing atomic number. Elements are arranged by increasing

Group 2 MetalsGroup 2 Metals Known as Known as Alkaline Earth MetalsAlkaline Earth Metals Also extremely reactive, but not as Also extremely reactive, but not as

much as Alkali Metalsmuch as Alkali Metals Contain 2 valence electrons (they end Contain 2 valence electrons (they end

in sin s22)) They all form ions with a They all form ions with a +2+2 charge. charge.

Page 8: Unit 3 Periodic Table and Valence electrons. Modern Periodic Table Elements are arranged by increasing atomic number. Elements are arranged by increasing

Group 1 are the alkali metals Group 1 are the alkali metals (but NOT H)(but NOT H)

Group 2 are the alkaline earth metalsGroup 2 are the alkaline earth metalsH

Page 9: Unit 3 Periodic Table and Valence electrons. Modern Periodic Table Elements are arranged by increasing atomic number. Elements are arranged by increasing

Groups 3-12Groups 3-12 These groups are known as These groups are known as

Transition MetalsTransition Metals Not very Not very reactivereactive metals metals Generally have 2 valence electrons Generally have 2 valence electrons Some of their “d” orbital electrons Some of their “d” orbital electrons

jump around into “p” orbitals so jump around into “p” orbitals so many of these elements have more many of these elements have more than one possible than one possible positivepositive charge. charge.

Many form colorful ion solutions Many form colorful ion solutions (bright vibrant colors)(bright vibrant colors)

Page 10: Unit 3 Periodic Table and Valence electrons. Modern Periodic Table Elements are arranged by increasing atomic number. Elements are arranged by increasing

The The group B group B are called the are called the transition elementstransition elements

These are called the inner transition elements, and they belong here

Page 11: Unit 3 Periodic Table and Valence electrons. Modern Periodic Table Elements are arranged by increasing atomic number. Elements are arranged by increasing

Group 17Group 17 Known as Known as HalogensHalogens Extremely reactive nonmetals; reactivity Extremely reactive nonmetals; reactivity

increasesincreases up a group (Fluorine the most up a group (Fluorine the most active)active)

Have 7 valence electrons (eHave 7 valence electrons (e-- configuration configuration ends in sends in s22pp55))

Most of these elements are toxic in their Most of these elements are toxic in their natural statenatural state

Most are also Most are also diatomicdiatomic in their natural in their natural state (Fstate (F22, Br, Br22, Cl, Cl22, I, I22))

They all form ions with a They all form ions with a (-1)(-1) charge. charge.

Page 12: Unit 3 Periodic Table and Valence electrons. Modern Periodic Table Elements are arranged by increasing atomic number. Elements are arranged by increasing

Group 18Group 18 Known as Known as Noble gasesNoble gases UnreactiveUnreactive nonmetals nonmetals All have 8 valence electronsAll have 8 valence electrons (e- configuration ends in s(e- configuration ends in s22pp66), ),

except Helium (which has 2 except Helium (which has 2 electrons)electrons)

They do not form They do not form ionsions because they because they have a filled energy level!have a filled energy level!

Page 13: Unit 3 Periodic Table and Valence electrons. Modern Periodic Table Elements are arranged by increasing atomic number. Elements are arranged by increasing

Group 18 are the Group 18 are the noble gasesnoble gases Group 17 is called the Group 17 is called the halogenshalogens

Page 14: Unit 3 Periodic Table and Valence electrons. Modern Periodic Table Elements are arranged by increasing atomic number. Elements are arranged by increasing

Valence electronsValence electrons

Valence electrons are electrons Valence electrons are electrons located in the outermost energy located in the outermost energy level.level.

They are located only in the They are located only in the s and p s and p sublevelssublevels

These electrons are involved in These electrons are involved in chemical bonding.chemical bonding.

Page 15: Unit 3 Periodic Table and Valence electrons. Modern Periodic Table Elements are arranged by increasing atomic number. Elements are arranged by increasing

Electron ConfigurationsElectron Configurations

An element’s electron configuration An element’s electron configuration shows how many valence electrons it shows how many valence electrons it has.has.

Example:Example:

1s1s222s2s222p2p663s3s223p3p664s4s223d3d10104p4p44

Valence electrons = 6

Page 16: Unit 3 Periodic Table and Valence electrons. Modern Periodic Table Elements are arranged by increasing atomic number. Elements are arranged by increasing

PracticePractice

How many valence electrons do the How many valence electrons do the following elements have?following elements have?

1s1s222s2s222p2p663s3s223p3p664s4s223d3d10104p4p66

1s1s222s2s222p2p663s3s223p3p22

1s1s222s2s22

8 valence electrons

4 Valence Electrons

2 valence electrons

Page 17: Unit 3 Periodic Table and Valence electrons. Modern Periodic Table Elements are arranged by increasing atomic number. Elements are arranged by increasing

Octet RuleOctet Rule Most elements want to have 8 valence Most elements want to have 8 valence

electrons (exception He)electrons (exception He)

Elements will gain or lose electrons in Elements will gain or lose electrons in their valence shell in order to achieve an their valence shell in order to achieve an octet.octet.– This process forms This process forms IonsIons..

Ions have the same electron Ions have the same electron configuration as their nearest configuration as their nearest noble gasnoble gas..

Page 18: Unit 3 Periodic Table and Valence electrons. Modern Periodic Table Elements are arranged by increasing atomic number. Elements are arranged by increasing

Positive IonsPositive Ions Elements with less than 4 valence Elements with less than 4 valence

electrons electrons loselose their outermost “s” and their outermost “s” and “p” sublevel electrons .“p” sublevel electrons .

Loss of electrons Loss of electrons alwaysalways results in results in positive ions.positive ions.

ExampleExampleBe: 1sBe: 1s222s2s2 2 has 2 valence electrons has 2 valence electronsBeBe2+2+: 1s: 1s22 notice the ion has the samenotice the ion has the same

configuration as configuration as HeHe

MetalsMetals tend to form positive ions tend to form positive ions

Page 19: Unit 3 Periodic Table and Valence electrons. Modern Periodic Table Elements are arranged by increasing atomic number. Elements are arranged by increasing

Negative IonsNegative Ions Elements with more than 4 valence Elements with more than 4 valence

electrons electrons gaingain electrons in their electrons in their outermost “p” subleveloutermost “p” sublevel

Gain of electrons always results in Gain of electrons always results in negative ionsnegative ions

ExampleExampleO: 1sO: 1s222s2s222p2p44 has has 66 valence electrons valence electronsOO2-2-: 1s: 1s222s2s222p2p66 now has now has 88 valence valence

electrons just like Neelectrons just like Ne

Non-MetalsNon-Metals usually tend to form usually tend to form negative ionsnegative ions

Page 20: Unit 3 Periodic Table and Valence electrons. Modern Periodic Table Elements are arranged by increasing atomic number. Elements are arranged by increasing

Ion Formation SummaryIon Formation Summary Atoms gain or lose electrons to Atoms gain or lose electrons to

become more stable.become more stable.– They achieve the same electron They achieve the same electron

configuration as the Noble Gases.configuration as the Noble Gases.

Page 21: Unit 3 Periodic Table and Valence electrons. Modern Periodic Table Elements are arranged by increasing atomic number. Elements are arranged by increasing

Shorthand ConfigurationShorthand Configuration

S 16e-

Valence Electrons

Core Electrons

S 16e- [Ne] 3s2 3p4

1s2 2s2 2p6 3s2 3p4

Noble Gas Shorthand Electron Noble Gas Shorthand Electron ConfigurationsConfigurations

Longhand ConfigurationLonghand Configuration

Page 22: Unit 3 Periodic Table and Valence electrons. Modern Periodic Table Elements are arranged by increasing atomic number. Elements are arranged by increasing

Noble Gas Shorthand Noble Gas Shorthand ConfigurationConfiguration

Shorthand ConfigurationShorthand Configuration– Core eCore e--:: Go up one row and over to the Go up one row and over to the

Noble Gas.Noble Gas.

– Valence eValence e--:: On the next row, fill in the On the next row, fill in the # of e# of e-- in each sublevel. in each sublevel.

Page 23: Unit 3 Periodic Table and Valence electrons. Modern Periodic Table Elements are arranged by increasing atomic number. Elements are arranged by increasing

[Ar] 4s2 3d10 4p2

Noble Gas Shorthand Noble Gas Shorthand NotationNotation

Example - Example - GermaniumGermanium