Electron Configurations Electron Configurations Wrap UpWrap Up

The Layout of the Periodic TableThe Layout of the Periodic Table

Elements in the same families have very Elements in the same families have very similar electron configurations.similar electron configurations.All Alkali Metals end in sAll Alkali Metals end in s11

All Alkaline Earth Metals end in sAll Alkaline Earth Metals end in s22

Different chunks of the Periodic Table all Different chunks of the Periodic Table all have end in the same subshellshave end in the same subshells

The period number determines the highest The period number determines the highest shell that is occupied.shell that is occupied.

Lanthanum, Actinium, Lutetium, Lanthanum, Actinium, Lutetium, LawrenciumLawrencium

These don’t quite fit into our nice neat These don’t quite fit into our nice neat blocksblocks

Think of Lanthanum and Actinium being in Think of Lanthanum and Actinium being in the f blockthe f block

Think of Lutetium and Lawrencium being Think of Lutetium and Lawrencium being in the d blockin the d block

Losing and Gaining ElectronsLosing and Gaining Electrons

IonIon – an atom that has gained or lost – an atom that has gained or lost electrons.electrons.

2O

Patterns in Forming IonsPatterns in Forming Ions

Lots of atoms form ions that allow them to Lots of atoms form ions that allow them to get close to a noble gas electron get close to a noble gas electron configuration.configuration.

Noble gas configurations are especially Noble gas configurations are especially stablestable

Will lose or gain electrons depending on Will lose or gain electrons depending on which way it is easier to go.which way it is easier to go.

Patterns in Forming IonsPatterns in Forming Ions

Alkali Metals (Sodium)Alkali Metals (Sodium) Easiest to lose one electronEasiest to lose one electron

Alkaline Earth Metals (Magnesium)Alkaline Earth Metals (Magnesium) Easiest to lose two electronsEasiest to lose two electrons

Group 13 (Aluminum)Group 13 (Aluminum) Easiest to lose three electronsEasiest to lose three electrons

Group 14 (Carbon)Group 14 (Carbon) Can go both waysCan go both ways Can lose four electrons or gain four electronsCan lose four electrons or gain four electrons In reality does a variety of different things and is not In reality does a variety of different things and is not

always predictablealways predictable

Patterns in Forming IonsPatterns in Forming Ions

Group 15 (Nitrogen)Group 15 (Nitrogen)Easiest to gain 3 electronsEasiest to gain 3 electrons

Chalcogens (Oxygen)Chalcogens (Oxygen)Easiest to gain 2 electronsEasiest to gain 2 electrons

Halogens (Fluorine)Halogens (Fluorine)Easiest to gain 1 electronEasiest to gain 1 electron

Noble Gasses (Neon)Noble Gasses (Neon)Usually don’t reactUsually don’t react

Chemistry Always has Exceptions!Chemistry Always has Exceptions!

Some elements do not make it to a noble Some elements do not make it to a noble gas configuration.gas configuration.

GaGa3+3+ - is actually 1s - is actually 1s222s2s222p2p663s3s223p3p663d3d1010

Gallium ions do not follow the diagonal line Gallium ions do not follow the diagonal line diagram.diagram.

Pseudo-noble gas configurationsPseudo-noble gas configurations – stable – stable configurations with all occupied subshells configurations with all occupied subshells completely filled.completely filled.

Other Examples of ExceptionsOther Examples of Exceptions

CopperCopperExpect 1sExpect 1s222s2s222p2p663s3s223p3p664s4s223d3d99

Actually 1sActually 1s222s2s222p2p663s3s223p3p664s4s113d3d1010

Copper gains stability with a full d-subshellCopper gains stability with a full d-subshellChromiumChromium

Expect 1sExpect 1s222s2s222p2p663s3s223p3p664s4s223d3d44

Actually 1sActually 1s222s2s222p2p663s3s223p3p664s4s113d3d55

Chromium gains stability with a half-full d-Chromium gains stability with a half-full d-subshellsubshell

Transition Metal IonsTransition Metal Ions

Gets complicated because of the d-orbitalsGets complicated because of the d-orbitals

Typically form +2 ions but can have many Typically form +2 ions but can have many different chargesdifferent charges

Stable Electron ConfigurationsStable Electron Configurations

Least stable configurationLeast stable configurationPartially filled subshellPartially filled subshellHalf filled subshellHalf filled subshellFull subshellFull subshellNoble Gas ConfigurationNoble Gas Configuration

Most Stable ConfigurationMost Stable Configuration

Predicting Common Ion ChargesPredicting Common Ion Charges

You can predict charges on ions formed You can predict charges on ions formed from elements close to the Noble Gassesfrom elements close to the Noble GassesGroups 1 and 2, and the nonmetalsGroups 1 and 2, and the nonmetals

You are unlikely to be able to predict the You are unlikely to be able to predict the charge on anything elsecharge on anything else

The Octet “Rule”The Octet “Rule”Most stable ions have noble gas Most stable ions have noble gas

configurations configurations Xe = 1sXe = 1s222s2s222p2p663s3s223p3p664s4s223d3d10104p4p665s5s224d4d10105p5p66

Usually making the most stable ion leaves Usually making the most stable ion leaves 8 electrons in the outermost n shell 8 electrons in the outermost n shell For example: 5sFor example: 5s2 2 and 5p and 5p66

Valence electrons Valence electrons - the number of - the number of electrons in the outermost n shellelectrons in the outermost n shell

Core electrons Core electrons – non-valence electrons– non-valence electronsAll d and f electrons are core electrons. Why?All d and f electrons are core electrons. Why?

Valence ElectronsValence Electrons How many valence electrons does each family How many valence electrons does each family

have?have? Group 1 (Alkali Metals) have 1 valence electronGroup 1 (Alkali Metals) have 1 valence electron Group 2 (Alkaline Earth Metals) have 2 valence Group 2 (Alkaline Earth Metals) have 2 valence

electrons.electrons. Transition Metals and F-Blocks have 2 valence Transition Metals and F-Blocks have 2 valence

electrons.electrons. Group 13 has 3 valence electronsGroup 13 has 3 valence electrons Group 14 has 4 valence electronsGroup 14 has 4 valence electrons Group 15 has 5 valence electronsGroup 15 has 5 valence electrons Group 16 (Chalcogens) has 6 valence electronsGroup 16 (Chalcogens) has 6 valence electrons Group 17 (Halogens) has 7 valence electronsGroup 17 (Halogens) has 7 valence electrons Group 18 (Noble Gases) has 8 valence electronsGroup 18 (Noble Gases) has 8 valence electrons

Even More ShorthandEven More Shorthand

Based on the stability of the noble gas Based on the stability of the noble gas configurationsconfigurations

Noble gas becomes the “core” of the Noble gas becomes the “core” of the configuration.configuration.

Leave the outermost electrons alone Leave the outermost electrons alone because this is where the reactions because this is where the reactions happen.happen.

Condensed Electron ConfigurationsCondensed Electron Configurations

For silicon the electron configuration is For silicon the electron configuration is normally written 1snormally written 1s222s2s222p2p663s3s223p3p22

Find the previous noble gas Find the previous noble gas Put it in brackets in place of the electron Put it in brackets in place of the electron

configuration of the noble gas.configuration of the noble gas.For silicon the previous noble gas is Neon.For silicon the previous noble gas is Neon.Neon’s configurations is 1sNeon’s configurations is 1s222s2s222p2p66

Silicon = [Ne] 3sSilicon = [Ne] 3s223p3p22

Condensed Electron ConfigurationsCondensed Electron Configurations

Antimony, SbAntimony, Sb

Mercury, HgMercury, Hg

Fermium, FmFermium, Fm

Darmstadium, Ds, #110Darmstadium, Ds, #110

MORE Shorthand? AAAHHH! MORE Shorthand? AAAHHH! Lewis Dot Diagrams – using dots to Lewis Dot Diagrams – using dots to

represent the valence electrons of an atom.represent the valence electrons of an atom.Write the symbol of the element in the middle.Write the symbol of the element in the middle.Draw dots to represent the valence electrons Draw dots to represent the valence electrons

only.only.One side is used to represent the valence s One side is used to represent the valence s

orbital.orbital.Other three sides are used for valence p Other three sides are used for valence p

orbitals.orbitals.Must use Hund’s Rule for placing the electrons Must use Hund’s Rule for placing the electrons

in p orbitals.in p orbitals.

Lewis Dot Diagrams PracticeLewis Dot Diagrams PracticePotassiumPotassium

CalciumCalcium

ChromiumChromium

GalliumGallium

Lewis Dot Diagram PracticeLewis Dot Diagram Practice

GermaniumGermanium

ArsenicArsenic

SeleniumSelenium

BromineBromine

KryptonKrypton