Lesson 3.4 - Covalent Bonding

Forming covalent bonds

Covalent bonds are formed when atoms share electrons.

They occur between non-metals.

Forces

The forces between atoms are very strong.

In simple covalent structures, the intermolecular forces are weak. This gives these structures low melting and boiling points.

In giant covalent structures, the intermolecular forces are very strong. This makes these substances harder, with a higher melting and boiling point.

Polymers

Polymers are very large, covalent molecules.

They are made by joining together many monomers in a 'chain'.

Giant covalent structures

Giant covalent structures are very strong.

Some examples include:

• Diamond

• Silicon dioxide (sand)

• Graphene

Representing covalent bonds

We can represent covalent bonds using a:

• Dot and cross diagram

• Ball and stick model

• 2D diagram

• 3D diagram

Note that these diagrams are the same as in ionic compounds - they're very useful for many things!