The electronic configuration of two elements `X` and `Y` are given below:
`X` = `1s^2 2s^2 2p^6 3s^2 3p^6 4s^2` and `Y`= `1s^2 2s^2 2p^6 3s^2 3p^5` The formula of the ionic compound can be formed between these elements is

Options

A. `XY`
B. `XY_(2)`
C. `X_(2) Y`
D. `XY_(3)`

Answer

B

Explanation

`X (1s^(2) 2s^(2) 2p^(6) 3s^(2) 3p^(6) 4s^(2))` has two valence electrons `X^(2+)` .Since `Y( 1s^(2) 2s^(2) 2p^(6) 3s^(2) 3p^(5))` has one electrons less than the nearest noble gas configuration therefore it gain oen electron easily to form `Y^(-) `. To balance the charge two ions of `Y^(-)` combine with one ion of `X^(2+)` to form the compound `XY_(2)` i.e., option ( b) is correct.