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