K
F
Ca
Fe
N
Al
H
Cl
Li
Pb
1s2, 2s2, 2p5
1s1
[ Ar]4s1
[Xe ] 6s2, 4f14, 5d10, 6p2
[ Ne] 3s2, 3p1
1s2, 2s2, 2p3
[ Ar]4s2 3d6
1s2, 2s2, 2p6, 3s2, 3p5
1s2, 2s2, 2p6,3s2, 3p6, 4s2
[ He] 2s1