Electron Configuration &

The Periodic Table

• The periodic table is a tool

• Electron location can be determined using the periodic table

Energy Levels

• Each period represents an energy level

• Example: Period 1 consists of Hydrogen and Helium

1

2

3

4

5

6

7

H He

s2

s1S- block

The P-block p1 p2 p3 p4 p5 p6

d block

d1 d2 d3 d4 d5 d6 d7 d8 d9 d10

• D orbitals fill up after previous energy level so first d is 3d even though it’s in row 4.

1

2

3

4

5

6

7

3d

F - block

• Inner transition elements

f1 f5f2 f3 f4 f6 f7 f8 f9 f10 f11 f12 f14f13

Long Periodic Table

• f orbitals start filling at 4f

1

2

3

4

5

6

74f

5f

s, p, d, f

Electron Configuration & Ions

• Ion – atom that has gained or lost electrons

• Lose electrons – positive charge

• Gain electrons – negative charge

• Na � Na+ + e-

• 11 electrons � 10 electrons

• 1s22s22p63s1 � 1s22s22p6

Electron Configuration

ShorthandYes!! There is an easier way!

The Shorthand• Each period ends in a noble gas.

• This means the energy level is full!

• Write symbol of the noble gas (18) before the element.• Each shorthand should begin with a noble gas!

• Then the rest of the electrons.

• Aluminum

• Full configuration: 1s22s22p63s23p1

• Ne is 1s22s22p6

• So….. Al is [Ne] 3s23p1

More examples

•Ge = 1s22s22p63s23p64s23d104p2

•Ge = [Ar] 4s23d104p2

•Hf =1s22s22p63s23p64s23d104p65s2

4d105p66s24f145d2

•Hf =[Xe]6s24f145d2

The Shorthand Again

Sn- 50 electrons

The noble gas before it is Kr

[ Kr ]

Takes care of 36

Next 5s2

5s2

Then 4d10

4d10

Finally 5p2

5p2