- Atoms combine to attain a stable arrangement of eight electrons in their outer most shell.

- Ions are held together by strong electrostatic forces. Hence, ionic compounds have high melting and boiling points.

- Ionic compounds are good conductors of electricity . They are soluble in water but insoluble in inorganic solvents.

- Covalent bonds are formed by sharing of electrons between atoms.

- Covalent compounds have low melting and boiling points. They are poor conductors of electricity.

- The covalent compounds are generally insoluble in water but are soluble in organic solvents.

- Covalent bonds are directional in nature and hence covalent compounds have definite shapes.

- Bond length decreases with the number of bonds whereas the bond energy increases with the number of bonds.

- Electrons are mobile in metals and hence the metals and hence the metals are good conductors of electricity.

- Hydrogen bonding is an important interaction and is responsible for variety of properties in various molecules. In water, it is responsible for its liquid nature whereas, it is responsible for its liquid nature whereas in proteins it is responsible for their shape and in glucose it is responsible for its solubility in water.