Atoms

• An atom has a small positively charged nucleus surrounded by orbiting negatively charged electrons.
• Atoms have a radius of about 1 x 10-10 metres.
• Protons have a charge of +1 and a relative atomic mass of 1. The proton number is the amount of protons the atom has.
• Electrons have a charge of -1 and a relative atomic mass of 1/2000. The number of electrons is the same as the number of protons.
• Neutrons have no charge or 0, and have a relative atomic mass of 1.
• Sub shells are made up of orbitals.