Valence configuration and the periodic table

Look again carefully at the group valence configurations. They are really easy if you understand the filling of the subshells and know your periodic table.
s1 s2 s2d1 s2d2 s2d3 s1d5 s2d5 s2d6 s2d7 s2d8 s1d10 s2d10 s2p1 s2p2 s2p3 s2p4 s2p5 s2p6
  1
H
   
3Li 4Be   5B 6C 7N 8O 9F 10Ne
11Na 12Mg 13Al 14Si 15P 16S 17Cl 18Ar
19K 20Ca 21Sc 22Ti 23V 24Cr 25Mn 26Fe 27Co 28Ni 29Cu 30Zn 31Ga 32Ge 33As 34Se 35Br 36Kr
37Rb 38Sr 39Y 40Zr 41Nb 42Mo 43Tc 44Ru 45Rh 46Pd 47Ag 48Cd 49In 50Sn 51Sb 52Te 53I 54Xe
55Cs 56Ba 71Lu 72Hf 73Ta 74W 75Re 76Os 77Ir 78Pt 79Au 80Hg 81Tl 82Pb 83Bi 84Po 85At 86Rn
s-block
nsx
x 1, 2
d-block
ns2(n-1)dx
(x is 1- 10)
p-block
ns2 npx
(x is 1-6)


For s and p-block elements:
The shell number (given by n) in for the valence electrons is the period number.

For d block elements:
n for s electrons equals the period number n for d-electrons equals (period number -1).