Question

An element X belong to group 1 and 3 periods. (i) agive its electron confugation. (ii) Formula when it combine with oxygen.

Answer 1

Group 1 , so it's valance electron will be 1

Period 3 , it will have 3 shells

(I) 2,8,1

(2) X O

1 2

(Criss cross)

X2O

Hope it helps!!