Question

An element $X$ combines with oxygen to form an oxide $X_{2}O$. This oxide is electrically conducting.
(i) How many electrons would be there in the outermost shell of the element $X$
(ii) To which group of the periodic table does the element $X$ belong.
(iii) Write the formula of the compound which is formed when $X$ reacts with chlorine.

Answer 1

Valency of O is $2$. $X$ forms $X_{2}O$. Hence valency of $X$ is $1$. Thus it has $1$ electron for outermost shell. Hence it belongs to group IA. When $X$ reacts with chlorine it forms $XCl$.