Consider two elem

(i) Atomic no. of A = 17

Electronic configuration of A = 2, 8, 7

Since it has '7' electrons in its outermost shell.

So, group to which A belongs = 10 +7 = group 17.

Period to which element A belongs = no. of shells = 3

So, period to which A belongs is 3^rd

Atomic no. of B = 19

Electronic configuration of A = 2, 8, 8,1

Since it has '1' electrons in its outermost shell.

So, group to which B belongs = group 1.

Period to which element B belongs = no. of shells = 4

So, period to which B belongs is 4^th

(ii) Since, Valency of A = -1

Valency of B = +1

So, when A combines with B, the formula will be BA

(iii) The electron dot structure is as follows:

The bond formed between B and A is an ionic bond.