AP Notes Chapter 7 Electron Configuration Magnetism Periodic Trends

AP Notes Chapter 7AP Notes Chapter 7Electron Configuration

Magnetism

Periodic Trends

Aufbau PrincipleAufbau Principle

Aufbau is German for building up.Aufbau is German for building up. As the protons are added one by one, As the protons are added one by one,

the electrons fill up hydrogen-like the electrons fill up hydrogen-like orbitals.orbitals.

e- are added to atoms into the lowest e- are added to atoms into the lowest energy level & sub-level availableenergy level & sub-level available

Fill up in order of energy levels.Fill up in order of energy levels.

DetailsDetails Valence electronsValence electrons- the electrons in the - the electrons in the

outermost energy levels (not d).outermost energy levels (not d). Core electronsCore electrons- the inner electrons.- the inner electrons. Hund’s RuleHund’s Rule- The lowest energy - The lowest energy

configuration for an atom is the one configuration for an atom is the one that will have the maximum number that will have the maximum number of of unpaired unpaired electrons in the orbital.electrons in the orbital.

C 1sC 1s2 2 2s2s22 2p 2p22

max emax e--

n = 1n = 1

max emax e--

n = 1 s 2n = 1 s 2n = 2n = 2

max emax e--

n = 1 s 2n = 1 s 2n = 2 s 2 8 n = 2 s 2 8 p 6 p 6 n = 3n = 3

max emax e--= 2n= 2n22

n = 1 s 2n = 1 s 2n = 2 s 2 8 n = 2 s 2 8 p 6 p 6 n = 3 s 2n = 3 s 2 p 6 18 p 6 18 d 10 d 10

Pauli Exclusion PrinciplePauli Exclusion Principle nn ll mmll ss

11 00 0 0 +1/2+1/211 00 0 0 -1/2-1/222 00 0 0 +1/2+1/222 00 0 0 -1/2-1/222 11 -1 -1 +1/2+1/222 11 -1 -1 -1/2-1/2

22 11 0 0 +1/2+1/222 11 0 0 -1/2-1/2

22 11 1 1 +1/2+1/222 11 1 1 -1/2-1/2

Orbital

1S

2s

2p

Pauli Exclusion PrinciplePauli Exclusion Principle

No 2 eNo 2 e-- in same atom can in same atom can have the same set of four have the same set of four quantum numbersquantum numbers

Quantum #s___, ___, ___, ___ n ml ms

Electron ProbabilitySpace &

Quantum Numbers

Spin QN = mSpin QN = mss (s) (s)

spin of espin of e-- on own axis on own axis

2

1ms

Incr

easi

ng e

nerg

y

1s

2s

3s

4s

5s6s

7s

2p

3p

4p

5p

6p

3d

4d

5d

7p 6d

4f

5f

He with 2 electrons

Ne with 10 electrons

Ar with 18 electrons

Fill from the bottom up Fill from the bottom up following the arrowsfollowing the arrows

1s2s 2p3s 3p 3d4s 4p 4d 4f

5s 5p 5d 5f6s 6p 6d 6f7s 7p 7d 7f

• 1s2

• 2• electrons

2s2

• 4

2p6 3s2

• 12

3p6 4s2

• 20

3d10 4p6

5s2

• 38

4d10 5p6 6s2

• 56

7s 7p ...6s 6p 6d ...5s 5p 5d 5f ...4s 4p 4d 4f3s 3p 3d2s 2p1s

DetailsDetails Elements in the same column have Elements in the same column have

the same electron configuration.the same electron configuration. Put in columns because of similar Put in columns because of similar

properties.properties. Similar properties because of electron Similar properties because of electron

configuration.configuration. Noble gases have filled energy levels.Noble gases have filled energy levels. Transition metals are filling the d Transition metals are filling the d

orbitalsorbitals

ExamplesExamples33LiLi

66CC

88OO

1919KK

2424CrCr

2929CuCu

ExceptionsExceptions

Ti = [Ar] 4sTi = [Ar] 4s22 3d 3d22 V = [Ar] 4sV = [Ar] 4s22 3d 3d33

Cr = [Ar] 4sCr = [Ar] 4s11 3d 3d5 5

Mn = [Ar] 4sMn = [Ar] 4s22 3d 3d55

Half filled orbitals.Half filled orbitals. Scientists aren’t sure of why it Scientists aren’t sure of why it

happenshappens same for Cu [Ar] 4ssame for Cu [Ar] 4s11 3d 3d1010

All atoms want a noble All atoms want a noble gas or pseudo noble gas or pseudo noble gas configurationgas configuration

Atoms with full or half-fullAtoms with full or half-full

sub-levels are particularlysub-levels are particularly

stablestable

Gain or loss of eGain or loss of e-- produces ionsproduces ions

Consider: ZnConsider: Zn2+2+, Ag, Ag++, Cu, Cu2+2+

Energy Level DiagramEnergy Level Diagram

3d __ __ __ __ __3d __ __ __ __ __4s __4s __ 3p __ __ __ 3p __ __ __3s __ 3s __ 2p __ __ __ 2p __ __ __2s __2s __1s __ 1s __

Gain or loss of eGain or loss of e-- produces ionsproduces ions

Consider: ZnConsider: Zn2+2+, Ag, Ag++, Cu, Cu2+2+

Ions with full or half-full Ions with full or half-full sub-levels are particularly sub-levels are particularly

stablestable

Gain or loss of eGain or loss of e-- produces ionsproduces ions

Consider: NaConsider: Na++, Ne, F, Ne, F--

Energy Level DiagramEnergy Level Diagram

3d __ __ __ __ __3d __ __ __ __ __4s __4s __ 3p __ __ __ 3p __ __ __3s __ 3s __ 2p __ __ __ 2p __ __ __2s __2s __1s __ 1s __

Gain or loss of eGain or loss of e-- produces ionsproduces ions

Consider: NaConsider: Na++, Ne, F, Ne, F--

Chemical species with the Chemical species with the same esame e-- configuration are configuration are

ISOELECTRONICISOELECTRONIC

Diamagnetic - Slightly repelled by a strong magnet (moments counter each other e- are paired)

Paramagnetic – Attracted to magnetic field (moments not aligned e- are unpaired )

Ferromagnetic – Materials retain a magnetic field if one has been induced (moments are aligned e- are unpaired)

Trendsof the

Periodic Table

Triplet Trends Triplet Trends

Organize trends Organize trends Use only increasing properties Use only increasing properties Learn the diagonal NOT the two Learn the diagonal NOT the two

vectors that make up the diagonal….. vectors that make up the diagonal….. You can always recreate the two You can always recreate the two

vectors so you have less to learn or vectors so you have less to learn or memorizememorize

Atomic NumberAtomic Number Increases to the rightIncreases to the right Increases down Increases down

Atomic MassAtomic Mass Increases to the rightIncreases to the right Increases down Increases down

Nuclear ChargeNuclear Charge Increases to the rightIncreases to the right Increases down Increases down

Atomic RadiusAtomic Radius

Is taken as the covalent Is taken as the covalent radius for non-metallic radius for non-metallic elements and as the metallic elements and as the metallic radius for metalsradius for metals

Atomic RadiusAtomic Radius

Covalent radius is Covalent radius is one-half the one-half the distance between distance between the nuclei of two the nuclei of two identical atoms identical atoms that are singly that are singly bonded to one bonded to one another. another.

Atomic RadiusAtomic Radius Covalent radii for elements Covalent radii for elements

whose atoms do not bond whose atoms do not bond to one another can be to one another can be estimated by combining estimated by combining radii of those that do with radii of those that do with the distances between the distances between unlike atoms in various unlike atoms in various molecules.molecules.

Atomic RadiusAtomic Radius

Metallic radius is one-half Metallic radius is one-half the closest internuclear the closest internuclear distance in a metallic distance in a metallic crystal.crystal.

0

50

100

150

200

1 3 5 7 9 11 13 15 17 19

Atomic Number

Ato

mic

Rad

ius

(pm

)Atomic RadiusAtomic Radius

Atomic RadiusAtomic Radius

Ionic Radii SizeIonic Radii Size

Overall ActivityOverall Activity

Ionization EnergyIonization Energy

Is the energy required to Is the energy required to remove the outermost remove the outermost electron from an atom or a electron from an atom or a positive ion in the ground positive ion in the ground state. state.

First Ionization EnergyFirst Ionization Energy

Energy required to remove Energy required to remove the first electron from a the first electron from a neutral atom.neutral atom.

0

500

1000

1500

2000

2500

1 3 5 7 9 11 13 15 17 19

Atomic Number

1st

Ion

izat

ion

En

erg

y (k

J/m

ol)

First Ionization EnergyFirst Ionization Energy

First Ionization EnergyFirst Ionization Energy

First Ionization EnergyFirst Ionization Energy

Second Ionization Second Ionization EnergyEnergy Energy needed to remove Energy needed to remove

the outermost electron from the outermost electron from a +1 ion. a +1 ion.

Energy needed to remove Energy needed to remove the second electron from a the second electron from a neutral atom.neutral atom.

0

1000

2000

3000

4000

5000

6000

7000

8000

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20

Atomic Number

2nd

Io

niz

atio

n E

ner

gy

(kJ/

mo

l)

Second Ionization Second Ionization EnergyEnergy

Electron AffinityElectron Affinity

Energy released or Energy released or absorbed when an electron absorbed when an electron is added to the valence level is added to the valence level of a gas-phase atom.of a gas-phase atom.

-400

-350

-300

-250

-200

-150

-100

-50

0

50

100

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20

Atomic Number

Ele

ctro

n A

ffin

ity

(kJ/

mo

l)

Electron AffinityElectron Affinity

Electron AffinityElectron Affinity

ElectronegativityElectronegativity

Ability to bond & desire for electronsAbility to bond & desire for electrons