What is the smallest subatomic particle?

Subatomic particle

1. Particles that are smaller than the size of an atom are called subatomic particles.
2. Type of subatomic particles : (1) Leptons (2) Quarks
3. There exist six known quarks and six known leptons.

Quarks, Leptons, and, bosons

1. Quarks: These are elementary subatomic particles that associate with one another via the strong force to make up composite particles such as protons and neutrons. There are six types of quarks, which are :

1. up
2. down
3. charm
4. strange
5. top
6. bottom.

2. Leptons: These are $\frac{1}{2}$ integer spin fundamental particle, that responds only to the gravitational force, weak force, and electromagnetic force. Leptons appear as point-like particles, having no internal structure. There exist six known types of leptons, which are as follows:

1. electron
2. electron neutrino
3. muon
4. muon neutrino
5. tau
6. tau neutrino

3. Bosons: Bosons are those particles that have an integer spin (0, 1, 2…). All the force carrier particles are bosons. These are also known as force particles, as these control the interaction of physical forces, such as electromagnetism, gravity, etc.

Step 3. An illustrative diagram of quarks, leptons, and bosons is shown below.

Hence, leptons and quarks are the smallest subatomic particles.