Explanation:
As we know that the atomic number of lithium is 3 and its electronic distribution is 2, 1. Whereas atomic number of fluorine is 9 and its electronic distribution is 2, 7. So, for a metal it is easier to lose an electron rather than losing 2 or more number of electrons.
Also, fluorine is much more electronegative in nature. Hence, it will readily accept an electron from a donor atom. Therefore, a strong ionic bond will be present between lithium and fluorine atom.
On the other hand, atomic number of magnesium is 12 and its electronic configuration is 2, 8, 2. And, atomic number of oxygen is 8 and its electronic distribution is 2, 6. Also, oxygen is less electronegative than fluorine therefore, force of attraction exerted by oxygen to gain the valence electrons will not be strong enough.
Hence, the ionic bond between magnesium oxide is not strong enough.
Thus, we can conclude that ionic bond between lithium fluoride is stronger than ionic bond in magnesium oxide.
