Question

Outermost shells of two elements X and Y have one and six electrons respectively. If they combine, what will be expected formula of the compound?

Answer 1

Since X have one electron in outermost shell, it will lose one electron to complete it's octet and form $X^{+}$

$\to$ Y have six electron in outermost shell, it will gain two electrons to complete it's octet and form $Y^{2-}$

Formula of compound is $X_{2}Y$