Question

Which compound contains both ionic and covalent
bonds?
(1) CaCO3 (3) MgF2
(2) PCl3 (4) CH2O

Answer 1

(1) CaCO3 is your answer. The positive ion is $\text{Ca}^{2+$ and the negative radical ion is $\text{CO}_3^{-}$. There exists covalent bonds between the carbon and oxygen atoms in the $\text{CO}_3^{-}$.