1 Biological molecules

What is covalent bonding?

Atoms share a pair of electrons in their outer shells

As a result the outer shells of both atoms is filled and a more stable compound, called a molecule, is formed

What is ionic bonding?

Ions with opposite charges attract one another

This electrostatic attraction is known as an ionic bond

Ionic bonds are weaker than covalent bonds

What is a polar molecule?

A molecule with an uneven distribution of charge is said to be polarised

What is hydrogen bonding?

The electrons within a molecule are not evenly distributed but tend to spend more time at one position

This region is more negatively charged than the rest of the molecule

The negative region of one polarised molecule and the positively charged region of another attract each other

A weak electrostatic bond is formed between the two

Although each bond is individually weak, they can collectively form important forces that alter the physical properties of molecules (especially true for water)