The element X in group 17 has 3 shells. If so: What will be the chemical formula of the compound formed if the element X reacts with element Y of the third period which contains one electron in the p subshell?

Explanation

a) `1s^2 2s^2 2p^6 3s^2 3p^5`
ii) 3
c)`Y^3 + X^1- rarr YX_3`