1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3d 10 4p 6 5s 1 4d 6

1s
2
2s
2
2p
6
3s
2
3p
6
4s
2
3d
10
4p
6
5s
1
4d
6
[Kr]5s
1
4d
6
Tc# 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3d 10 4p 6 5s 2 4d 5 [Kr]5s 2 4d 5
Ru* 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3d 10 4p 6 5s 1 4d 7 [Kr]5s 1 4d 7
Ru# 1s
2
2s
2
2p
6
3s
2
3p
6
4s
2
3d
10
4p
6
5s
2
4d
6
[Kr]5s
2
4d
6
Rh* 1s
2
2s
2
2p
6
3s
2
3p
6
4s
2
3d
10
4p
6
5s
1
4d
8
[Kr]5s
1
4d
8
Rh# 1s
2
2s
2
2p
6
3s
2
3p
6
4s
2
3d
10
4p
6
5s
2
4d
7
[Kr]5s
2
4d
7
Pd* 1s
2
2s
2
2p
6
3s
2
3p
6
4s
2
3d
10
4p
6
4d
10
[Kr]4d
10
Pd# 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3d 10 4p 6 5s 2 4d 8 [Kr]5s 2 4d 8
Ag * 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3d 10 4p 6 5s 1 4d 10 [Kr]5s 1 4d 10
Ag# 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3d 10 4p 6 5s 2 4d 9 [Kr]5s 2 4d 9
Cd 1s
2
2s
2
2p
6
3s
2
3p
6
4s
2
3d
10
4p
6
5s
2
4d
10
[Kr]5s
2
4d
10
* These are exceptions which you do not need to memorize.
# Use these instead
7 of 12

Chemistry 143 Electron Configurations Dr. Caddell
NAME:_______Key___________ SECTION:________________
+1 Cations
Remember, when forming cations always take electrons out of the
highest occupied “n” orbital first!
Element Expanded Electron Configuration Core Notation
Li
+
1s
2
Not for this one
Na
+
1s
2
2s
2
2p
6
[He]2s
2
2p
6
K + 1s 2 2s 2 2p 6 3s 2 3p 6 [Ne]3s 2 3p 6
Rb
+
1s
2
2s
2
2p
6
3s
2
3p
6
4s
2
3d
10
4p
6
[Ar]4s
2
3d
10
4p
6
Cs
+
1s
2
2s
2
2p
6
3s
2
3p
6
4s
2
3d
10
4p
6
5s
2
4d
10
5p
6
[Kr]5s
2
4d
10
5p
6
Fr
+
1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3d 10 4p 6 5s 2 4d 10 5p 6 6s 2 4f 14 5d 10 6p 6 [Xe]6s 2 4f 14 5d 10 6p 6
Ga + 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3d 10 [Ar]4s 2 3d 10
Cu
+
1s
2
2s
2
2p
6
3s
2
3p
6
3d
10
[Ar]3d
10
Ag
+
* 1s
2
2s
2
2p
6
3s
2
3p
6
4s
2
3d
10
4p
6
4d
10
[Kr]4d
10
Ag + # 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3d 10 4p 6 5s 1 4d 9 [Kr]5s 1 4d 9
Tl
+
1s
2
2s
2
2p
6
3s
2
3p
6
4s
2
3d
10
4p
6
5s
2
4d
10
5p
6
6s
2
4f
14
5d
10
[Xe]6s
2
4f
14
5d
10
* This is an exception which you do not need to memorize.
# Use this instead
8 of 12

Chemistry 143 Electron Configurations Dr. Caddell
NAME:________Key__________ SECTION:________________
+2 Cations
Remember, when forming cations always take electrons out of the
highest occupied “n” orbital first!
Element Expanded Electron Configuration Core Notation
Be 2+
1s 2 Not for this one
Mg
2+
1s
2
2s
2
2p
6
[He]2s
2
2p
6
Ca
2+
1s
2
2s
2
2p
6
3s
2
3p
6
[Ne]3s
2
3p
6
Sr 2+ 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3d 10 4p 6 [Ar]4s 2 3d 10 4p 6
Ba
2+
1s
2
2s
2
2p
6
3s
2
3p
6
4s
2
3d
10
4p
6
5s
2
4d
10
5p
6
[Kr]5s
2
4d
10
5p
6
Ra
2+
1s
2
2s
2
2p
6
3s
2
3p
6
4s
2
3d
10
4p
6
5s
2
4d
10
5p
6
6s
2
4f
14
5d
10
6p
6
[Xe]6s
2
4f
14
5d
10
6p
6
Fe
2+
1s 2 2s 2 2p 6 3s 2 3p 6 3d 6 [Ar]3d 6
Cu 2+ 1s 2 2s 2 2p 6 3s 2 3p 6 3d 9 [Ar]3d 9
Zn
2+
1s
2
2s
2
2p
6
3s
2
3p
6
3d
10
[Ar]3d
10
Cd
2+
1s
2
2s
2
2p
6
3s
2
3p
6
4s