Question

State the type of bonding in the following molecules:​
(i) Water​
(ii) Calcium oxide

Answer 1

(i) Water: $H_{2}O$ (water) is a covalent compound because of the low difference in the electronegativity of hydrogen and oxygen atoms due to which the hydrogen and oxygen atoms share electrons with each other forming polar covalent bonds.

(ii) Calcium oxide: Calcium oxide is considered an ionic compound as it comprises a metal (calcium) and a nonmetal (oxygen). Secondly, due to the large difference of electronegativities, the calcium atom easily loses two of its outermost shell electrons, which are in turn, gained by the oxygen atom. So, it has ionic bonding.​
Ca → ${Ca}^{2+}$ + ${2e}^{-}$​
O + ${2e}^{-}$​ → $O^{2-}$