Matter is made of atoms and molecules. It depends on how many there are. Gases are matter made of single atoms or molecules that are very far apart, moving rapidly. Often we can't see the gas at all.
Solids are atoms and molecules jammed closely together.
No matter what the state, if you could magnify it a gazillion times, you would see that the matter is still made up of individual atoms or molecules. It is made of even smaller particles called neutrons, protons and electrons arranged in a particular way. Neutrons and protons are clustered together in the center of the atom, called the nucleus . Each proton has a positive charge. Outside the nucleus, the rest of the atom is mostly empty space.