Atoms are made up of protons, neutrons and electrons. The proton and the neutron make up the nucleus of the atom, and the electron orbits around the nucleus.
Electrons belong to a sub-group of atomic particles called leptons. Right now electrons are referred to as 'elementary particles' because they have no known components or substructure.
Protons belong to the baryon sub-group of atomic particles. They are made up of quarks. Neutrons also belong to the baryon group and are made of quarks.
Atoms possessing different amounts of protons, neurons and electrons can have varying properties including mass, conductivity, how well it reacts with other atoms etc. This is why we can have such a range of objects built up of atoms, they all react with each other in completely unique ways.
Quarks are also considered to be 'elementary particles'. There are 6 different types of quarks, all with different intrinsic properties. These quarks can combine, with other quarks and gluons (which mediate the binding forces), in multiple different ways to make up any particle in the 'hadron' sub-group of atomic particles (for example: baryons and mesons).