These are forces of attraction that hold molecules together in a substance. There are two types of intermolecular forces namely;

19. Hydrogen bonding
19. Vander Waals forces

1. Hydrogen Bonding

The molecules here must possess hydrogen and an electronegative element such as F, O and N. Since oxygen has two lone pairs of electrons it will turn to donate a pair to it atoms.

An example of hydrogen bonding is seen in water (H₂O).

2. Vander Waals Forces

These are weak forces of attraction that holds different layers in graphite together.

1. Metallic Bonding

It involves metals only. The valence electrons in a metal are delocalized to form positively charged ions. A metallic crystal consists of a group of positively charged ions, embedded in a set of electrons. The attraction between the positive ions and the sea of electrons constitutes a metallic bond.

Properties of Metals as a Result of Metallic Bonding

• In their solid state, they are good conductors of heat and electricity because they have delocalized electrons.
• Some have high melting and boiling points because they are held tightly together.