Question

An element $X$ combines with oxygen to form an oxide $X_{2}O$. To which group of the periodic table does the element $X$ belong?

• A. group $1$
  
• B. group $3$
  
• C. group $5$
  
• D. group $7$
  

Answer 1

The correct option is A group $1$

$2X^{+1}+O^{2-}⟶X_{2}O$
$X$ has a valency of $+1$.

Hence, from the above-given options, X belongs to group 1.