Alpha-particle scattering experiment
- The atoms of all elements are made up of three types of particles: protons, neutrons and electrons.
Structure of an atom
Protons and neutrons are found in the nucleus of an atom while electrons orbit the nucleus
Table of properties of subatomic particles
Particle | Relative charge | Relative mass |
Proton | +1 | 1 |
Neutron | 0 | 1 |
Electron | -1 | 1/2000 (negligible) |
- A stable atom is neutral (it has no charge)
- Since protons and electrons have the same charge, but opposite signs, a stable atom has an equal number of both for the overall charge to remain neutral
Examiner Tip
Remember not to mix up the ‘atom’ and the ‘nucleus’. The ‘atom’ consists of the nucleus and electrons. The ‘nucleus’ just consists of the protons and neutrons in the middle of the atom, not the electrons.