Q14P - Chemistry: Molecular Nature Of Matter And Change

Question

How do the physical properties of a network covalent solid and a molecular covalent solid differ? Why?

Step-by-Step Solution

Answer

The properties of network solid reflect the necessity of breaking chemical bonds throughout the substances, whereas the properties of molecular solids reflect the weaker force between individual molecules. Eg, boron is network covalent metalloid black, hard, and has a very high melting point.

Step 1: Covalent solid

Covalent solid comprises covalently bonded atoms into a three-dimensional network of two-dimensional networks whereas molecular solids comprise discrete molecules held together by intermolecular forces.

Step 2: Explanation

Generally, network solids have very high melting and boiling points and are very hard. The molecular solids have low melting and boiling points and are soft.

The properties of network solid reflect the necessity of breaking chemical bonds throughout the substances, whereas the properties of molecular solids reflect the weaker force between individual molecules. Eg, boron is network covalent metalloid black, hard, and has a very high melting point.