Valence electron configurations

The valence configuration can be deduced from the periodic table position.
 

• All elements in a group have the same number of valence electrons.
   
• All elements in a group have their valence electrons in the same subshells.
  

  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)

  
   
• Elements in s-block have their valence electrons in an s-subshell.
   
• Elements in p-block have their valence electrons both in an s-subshell (always ns²) and a p-subshell (np^x where x is between 1 and 6).  See example below.
   
• Elements in d-block have their valence electrons both in an s-subshell and a d-subshell (nd^x where x is between 1 and 10). See example below.
   
• For s- and p-orbitals, the shell is the period number (n).
   
• For d-orbitals, the shell is n-1.