Is anatom is not a basic unit of matter?

Answer 1

Generally, the atom is seen as the basic unit of matter because the configuration of atoms make up the elements that make up what we see. However, digging deeper, the fundamental unit of matter is called a Quark. Quarks combine to form what is called Hadrons. The most stable hadrons are protons and neutrons, which then make up the nucleus of an atom.

However, it depends on the definition of matter. Even though the atom consists of other fundamental particles they do not have the same properties of the atom. The atom is the fundamental particle that can still exhibit properties of matter.