JAMB Chemistry 2013 Paper

Concept:The bond type depends on whether the atoms transfer or share electrons based on their electron configurations.Explanation:The configuration $1s^2\,2s^2\,2p^6\,3s^2$ represents magnesium, which has 2 valence electrons and tends to lose them to form $\mathrm{Mg}^{2+}$.The configuration $1s^2\,2s^2\,2p^4$ represents oxygen, which has 6 valence electrons and tends to gain 2 electrons to form $\mathrm{O}^{2-}$.The transfer of electrons from Mg to O produces oppositely charged ions that attract each other, forming an ionic bond.Answer:D. ionic