Electron SublevelsElectron Sublevels

Energy LevelsEnergy Levels

Originally taught simplistic viewOriginally taught simplistic view

7 levels7 levels Level 1 = 2 electrons maxLevel 1 = 2 electrons max Level 2 = 8 electrons maxLevel 2 = 8 electrons max Level 3 = 18 electrons maxLevel 3 = 18 electrons max Level 4 = 32 electrons maxLevel 4 = 32 electrons max Etc.Etc.

Reality - Levels are actually broken into sublevelsReality - Levels are actually broken into sublevels

2

Sublevels

P

S

Can hold 6 electrons max

Can hold 2 electrons max

Example:Example: Second level is broken into 2 sublevelsSecond level is broken into 2 sublevels Holds 8 electrons totalHolds 8 electrons total

S sublevel holds 2 maxS sublevel holds 2 max

P sublevel holds 6 maxP sublevel holds 6 max

Fills from bottom to topFills from bottom to top

3

Sublevels

P

S

Can hold 6 electrons max

Can hold 2 electrons max

D Can hold 10 electrons max

Example:Example: Third level is broken into 3 sublevelsThird level is broken into 3 sublevels Holds 18 electrons totalHolds 18 electrons total

S sublevel holds 2 maxS sublevel holds 2 max

P sublevel holds 6 maxP sublevel holds 6 max

D sublevel holds 10 maxD sublevel holds 10 max

Fills from bottom to topFills from bottom to top

Writing SublevelsWriting SublevelsWrite: Level, sublevel, electronsWrite: Level, sublevel, electrons

Written as 2sWritten as 2s22 and 2p and 2p66

The exponents represent electronsThe exponents represent electrons

Can be less than max. in that level.Can be less than max. in that level. Example: 2sExample: 2s1 1 or 2por 2p22 or 2p or 2p55

2

P

S

Can hold 6 electrons max

Can hold 2 electrons max

•2p6

•2s2

Simplistic View vs. SublevelsSimplistic View vs. Sublevels

1s1s22 =2=2

2s2s22 2p 2p66 =8=8

3s3s22 3p 3p66 3d 3d1010 =18=18

4s4s22 4p 4p66 4d 4d1010 4f 4f1414 =32=32

Sublevels added together still add to simplistic view

ProblemProblemLevels don’t fill in a neat order.Levels don’t fill in a neat order.They overlap each other and get mixed together.They overlap each other and get mixed together.Fill from the bottom to the topFill from the bottom to the top

4

3

4S fills before 3D

3s

4f

4d

3d

4s

3p

4p

1

2

5

4

3

3s

4f

4d

3d

4s

3p

4p5s

2p

2s

1s

5d

5p6s

6p

6

Fill OrderFill Order

The actual order is a mess.The actual order is a mess.

1s1s222s2s22 2p 2p66 3s 3s22 3p 3p66 4s 4s22 3d 3d10 10 4p4p66 5s 5s22 4d 4d1010 5p5p66 6s 6s22 4f 4f1414 5d 5d1010 6p 6p66 7s 7s22 5f 5f1414 6d 6d1010

7p7p66 5g 5g1818 6f 6f1414 7d 7d1010 etc. etc.

Can be memorized.Can be memorized.

1s1s22

2s2s22 2p 2p66

3s3s22 3p 3p66 3d 3d1010

4s4s22 4p 4p66 4d 4d1010 4f 4f1414

5s5s22 5p 5p66 5d 5d1010 5f 5f1414 5g 5g1818

6s6s22 6p 6p66 … …

Arranging SublevelsArranging Sublevels

1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s2 4d10

Draw diagonal lines to figure out the fill order.

1s1s22

2s2s22 2p 2p66

3s3s22 3p 3p66 3d 3d1010

4s4s22 4p 4p66 4d 4d1010 4f 4f1414

5s5s22 5p 5p66 5d 5d1010 5f 5f1414 5g 5g1818

Writing ElementsWriting Elements

1s2 2s2 2p6 3s2

Example: Magnesium has 12 electrons

1s 1s

2s 2p 2s 2p

3s 3p 3d3s 3p 3d

4s 4p 4d 4f4s 4p 4d 4f

5s 5p 5d 5f 5g5s 5p 5d 5f 5g

Writing ElementsWriting Elements

1s2 2s2 2p6 3s1

Example: Sodium has 11 electrons

Notice that the 3s sublevel is not full

Valence ElectronsValence Electrons

Writing sublevels is done to figure out the Writing sublevels is done to figure out the number of valence electronsnumber of valence electrons

Valence electrons determine how an atom Valence electrons determine how an atom reactsreacts

The number of electrons in the highest The number of electrons in the highest levellevel

Determining Valence ElectronsDetermining Valence ElectronsExample: Magnesium

•1s2 2s2 2p6 3s2

•2 valence electrons

•3 is the highest level and there are 2 electrons

Example: Phosphorus

•1s2 2s2 2p6 3s2 3p3

•5 valence electrons

•3 is the highest level and there are 5 electrons total

Example: Iron

•1s2 2s2 2p6 3s2 3p6 4s2 3d6

•2 valence electrons

•4 is the highest level and there are 2 electrons

EndEnd

1s 1s

2s 2p 2s 2p

3s 3p 3d3s 3p 3d

4s 4p 4d 4f4s 4p 4d 4f

5s 5p 5d 5f 5g5s 5p 5d 5f 5g

6s 6p …6s 6p …

Order ChartOrder Chart

Draw diagonal lines to figure out the fill order.

1s1s22

2s2s22 2p 2p66

3s3s22 3p 3p66 3d 3d1010

4s4s22 4p 4p66 4d 4d1010 4f 4f1414

5s5s22 5p 5p66 5d 5d1010 5f 5f1414 5g 5g1818

6s6s22 6p 6p66 … …

Order ChartOrder Chart

Draw diagonal lines to figure out the fill order.