Particles in Matter: Atoms and Molecules

• All matter is made up of subunits.

• There are two main types of subunits: atoms and molecules.

Atoms

• Atoms are the basic unit of matter.

• There are about 90 different types of atoms that exist naturally and more than 20 that have been synthesised artificially.

• Examples of atoms include helium atoms, carbon atoms and copper atoms.

Atoms are too small to see individually, but they can be represented as simple spheres.

Molecules

• Molecules are chemical structures made up of two or more atoms held in a fixed arrangement.

• These atoms are held together by forces of attraction known as chemical bonds.

• Molecules can consist of just one type of atom, but more often they consist of more than one type of atom.

• Molecules can contain as littles as two atoms in total, or they can contain many thousands of atoms.

• Due to the infinite number of ways that different atoms can combine, there is an almost unlimited number of different molecules that can exist.

Hydrogen molecules consist of two hydrogen atoms.
Ethanol molecules consist of two carbon atoms, six hydrogen atoms and one oxygen atom.