Question

17.
The electronic configuration of metal 'M' is 1s 2s
and of the non metal 'X' is 1s2 2s22p3. When these
two elements combines, the formula of the
compound will be
(1) MX
(2) MX
(3) M2X3
(4) MX2​

Answer 1

MX2 is the answer because

M - valency = 2

atomic no. 4

X-valency= 1

atomic no. =7