Answer:
it tells us of the specific amount of energy required to change the state of one mole of a substance either from solid to liquid or liquid to gas and vice versa without change in temperature
The answer to your question is
D: Unshared Pair
Hope this helps you :))))
Al2O3 has a higher melting point than Na2O. This is because the ionic bond between Al3+ ions and O2- ions is stronger than that between Na+ and O2-. The charge on the Al3+ ion is larger than that of the Na+ ion
