Question

Explain why:
(a) covalent compounds have generally low melting points.
(b) ionic compounds have generally high melting points.

Answer 1

(a) Covalent compounds are made up of electrically neutral molecules. So the force of attraction between the molecules is very weak. Only a small amount of heat energy is required to break these weak molecular forces, due to which covalent compounds have a low melting point.

(b) Ionic compounds have generally high melting points because ionic compounds are composed of positively and negatively charged ions. So there is a strong force of attraction between these ions. A large amount of heat energy is required to break this strong force of attraction and hence they have a high melting point.