neutron

Everyday

1. A neutron is one of the tiny particles inside the centre (nucleus) of an atom. tree →
2. A neutron has no electric charge — it is neutral, neither positive nor negative. tree →

In the lessons

In science lessons, the atom is made of protons (positive), neutrons (no charge) and electrons (negative); protons and neutrons sit in the nucleus, electrons move around it. Neutrons are important in nuclear power stations, where they split atoms. A neutron star is what is left after some huge stars explode: very small and very heavy. Phrases: «protons and neutrons», «neutron star», «number of neutrons».

Examples

• An atom has protons, neutrons and electrons. tree →
• A neutron has no charge. tree →
• Protons and neutrons are packed together in the nucleus. tree →
• A neutron star is smaller than a city but heavier than the Sun. tree →
• Most hydrogen atoms have no neutrons at all. tree →
• Neutrons help split atoms in a nuclear power station. tree →

Note

Easy way to remember: Neutron = Neutral. A proton and a neutron weigh about the same; an electron is much lighter. Maths: number of neutrons = mass number − number of protons. Do not confuse with «neuron», a nerve cell in the brain.