Is there anything smaller than an atom?

Yes, there are particles smaller than atoms. Atoms are composed of even smaller particles called subatomic particles. The three main subatomic particles are protons, neutrons, and electrons.

Protons and neutrons are found in the nucleus of an atom, and they are composed of even smaller particles called quarks. Quarks are considered fundamental particles, meaning they are not composed of smaller constituents (as far as we currently know).

Electrons are much smaller than protons and neutrons and are found orbiting the nucleus in regions called electron clouds. Electrons are often treated as point particles in many contexts, although in quantum mechanics, they are described by a wave function spread out in space.

In addition to protons, neutrons, and electrons, there are many other subatomic particles that have been discovered through experiments in particle physics, such as muons, neutrinos, photons, and many others. These particles can be smaller than atoms and play fundamental roles in the structure and behavior of matter.