Question

How does the number of:
valence electrons and 

Answer 1

The number of valence electrons increases by one as we move from left to right in a period. The group number 1 and 2 have 1 and 2 valence electrons respectively while group 13 to 18 have group number minus 10 = valence electrons. So, group 13 to 18 have 3, 4, 5, 6, 7 and 8 valence electrons respectively.