Question

An element X of atomic number 12 combines with an element Y of atomic number 17 to form a compound XY₂. State the nature of chemical bond in XY₂ and show how the electron configurations of X and Y change in the formation of this compound.

Answer 1

Compound XY₂ will have ionic bonds because it is formed by transfer of electrons from atoms of element X to atoms of element ​Y.
On forming the compound XY₂, each atom of element X that has 12 electrons with an electronic configuration of 2,8,2, donates its two electrons to give X²⁺ ion that has an electronic configuration of 2,8. Similarly, each atom of Y that has 17 electrons with electronic configuration 2,8,7 completes its octet by gaining one electron to form Y^- ion that has an electronic configuration of 2,8,8.