1

Electron Electron Filling Filling OrderOrder

Figure 8.5Figure 8.5

2

Electron Configurations Electron Configurations and the Periodic Tableand the Periodic Table

Figure 8.7

3

Relationship of Electron Relationship of Electron Configuration and Region Configuration and Region

of the Periodic Tableof the Periodic Table

• Gray = s blockGray = s block

• Orange = p blockOrange = p block

• Green = d blockGreen = d block

• Violet = f blockViolet = f block

4

PhosphorusPhosphorusPhosphorusPhosphorus

All Group 5A All Group 5A elements have elements have [core ] ns[core ] ns2 2 npnp3 3

configurations configurations where n is the where n is the period number.period number.

Group 5AGroup 5A

Atomic number = 15Atomic number = 15

1s1s2 2 2s2s2 2 2p2p6 6 3s3s2 2 3p3p33

[Ne] 3s[Ne] 3s2 2 3p3p33

1s

2s

3s3p

2p

5

LithiumLithiumLithiumLithium

Group 1A

Atomic number = 3

1s22s1 ---> 3 total electrons

1s

2s

3s3p

2p

6

Electron PropertiesElectron Properties

Diamagnetic: NOT attracted to a magnetic fieldParamagnetic: substance is attracted to a magnetic field. Substance has unpaired electrons.

Diamagnetic: NOT attracted to a magnetic fieldParamagnetic: substance is attracted to a magnetic field. Substance has unpaired electrons.

7

8

NeonNeonNeonNeon

Group 8A

Atomic number = 10

1s2 2s2 2p6 --->

Diamagnetic

1s

2s

3s3p

2p

9

BerylliumBerylliumBerylliumBeryllium

Group 2A

Atomic number = 4

1s22s2

Diamagnetic

1s

2s

3s3p

2p

10

BoronBoronBoronBoron

Group 3A

Atomic number = 5

1s2 2s2 2p1

Paramagnetic

1s

2s

3s3p

2p

11

CarbonCarbonCarbonCarbon

Group 4A

Atomic number = 6

1s2 2s2 2p2

Paramagnetic1s

2s

3s3p

2p

12

FluorineFluorineFluorineFluorine

Group 7A

Atomic number = 9

1s2 2s2 2p5 --->

Paramagnetic

1s

2s

3s3p

2p

13

Ion ConfigurationsIon ConfigurationsIon ConfigurationsIon Configurations

How do we know the configurations of ions?

Determine the magnetic properties of ions.

Ions with UNPAIRED ELECTRONS are

PARAMAGNETIC.

Without unpaired electrons DIAMAGNETIC.

14

transition metal ionstransition metal ionstransition metal ionstransition metal ions

Fe [Ar] 4s2 3d6 loses 2 electrons ---> Fe2+ [Ar] 4s0 3d6

• loses 3 electrons ---> Fe3+ [Ar] 4s0 3d5

4s 3d 3d4s

Fe Fe2+

4s 3d 3d4s

Fe Fe2+

15

Transition MetalsTransition Metals

How do they fill? How can we determine?

CopperCopperIronIron

ChromiumChromium

16

Ion Configurations MnIon Configurations MnIon Configurations MnIon Configurations Mn

Mn [Ar] 4s2 3d5 ---> Mn5+ [Ar] 4s03d2

loses 5 electrons ---> Mn5+ [Ar] 4s2 3d0

4s 3d 3d4s

Fe Fe2+D P

17

PERIODIPERIODIC C

TRENDSTRENDS

PERIODIPERIODIC C

TRENDSTRENDS

18

Effective Nuclear Charge, Effective Nuclear Charge, Z*Z*

Effective Nuclear Charge, Effective Nuclear Charge, Z*Z*

• Z* is the nuclear charge experienced by Z* is the nuclear charge experienced by the outermost electrons.the outermost electrons. See p. 295 and Screen 8.6.See p. 295 and Screen 8.6.

• Explains why E(2s) < E(2p)Explains why E(2s) < E(2p)

• Z* increases across a period owing to Z* increases across a period owing to incomplete shielding by inner electrons.incomplete shielding by inner electrons.

• Estimate Z* by --> [ Estimate Z* by --> [ Z - (no. inner electrons) Z - (no. inner electrons) ]]

• Charge felt by 2s e- in Li Charge felt by 2s e- in Li Z* = 3 - 2 = 1 Z* = 3 - 2 = 1

• Be Be Z* = 4 - 2 = 2Z* = 4 - 2 = 2

• B B Z* = 5 - 2 = 3Z* = 5 - 2 = 3 and so on!and so on!

19

Effective Nuclear Charge, Effective Nuclear Charge, Z*Z*

Effective Nuclear Charge, Effective Nuclear Charge, Z*Z*

• Z* is the nuclear charge experienced by Z* is the nuclear charge experienced by the outermost electrons.the outermost electrons. See p. 295 and Screen 8.6.See p. 295 and Screen 8.6.

• Explains why E(2s) < E(2p)Explains why E(2s) < E(2p)

• Z* increases across a period owing to Z* increases across a period owing to incomplete shielding by inner electrons.incomplete shielding by inner electrons.

• Estimate Z* by --> [ Estimate Z* by --> [ Z - (no. inner electrons) Z - (no. inner electrons) ]]

• Charge felt by 2s e- in Li Charge felt by 2s e- in Li Z* = 3 - 2 = 1 Z* = 3 - 2 = 1

• Be Be Z* = 4 - 2 = 2Z* = 4 - 2 = 2

• B B Z* = 5 - 2 = 3Z* = 5 - 2 = 3 and so on!and so on!

20

EffectiveEffective Nuclear Charge, Z* Nuclear Charge, Z*

• Atom Z* Experienced by Electrons in Valence Orbitals

• Li +1.28

• Be -------

• B +2.58

• C +3.22

• N +3.85

• O +4.49

• F +5.13

Increase in Increase in Z* across a Z* across a periodperiod

21General Periodic General Periodic TrendsTrends

• Atomic and ionic sizeAtomic and ionic size

• Ionization energyIonization energy

• Electron affinityElectron affinity

Higher effective nuclear chargeElectrons held more tightly

Larger orbitals.Electrons held lesstightly.