Fundamental particles

Need to know

What you need to know

• **Strong Nuclear Force:** The strongest force, but has a very short range (~10⁻¹⁵ m). It holds quarks together to form protons and neutrons, and binds protons and neutrons together in the nucleus. It affects hadrons.
• **Electromagnetic Force:** Weaker than the strong force, but has an infinite range. It acts between electrically charged particles. It holds atoms and molecules together.
• **Weak Nuclear Force:** Weaker still, and has an even shorter range (~10⁻¹⁸ m). It is responsible for radioactive decay, as it can change the flavour of quarks and leptons (e.g., in beta decay).
• **Gravitational Force:** The weakest of the four forces, but has an infinite range. It acts between all particles with mass. While dominant on a cosmic scale, its effect is negligible at the subatomic level.

Explanation

Fundamental particles

1. **Strong Nuclear Force:** The strongest force, but has a very short range (~10⁻¹⁵ m). It holds quarks together to form protons and neutrons, and binds protons and neutrons together in the nucleus. It affects hadrons.
2. **Electromagnetic Force:** Weaker than the strong force, but has an infinite range. It acts between electrically charged particles. It holds atoms and molecules together.
3. **Weak Nuclear Force:** Weaker still, and has an even shorter range (~10⁻¹⁸ m). It is responsible for radioactive decay, as it can change the flavour of quarks and leptons (e.g., in beta decay).
4. **Gravitational Force:** The weakest of the four forces, but has an infinite range. It acts between all particles with mass. While dominant on a cosmic scale, its effect is negligible at the subatomic level.