All atoms have 3 constituent particles: protons, neutrons and electrons. (The exception here is the isotope of hydrogen with mass number 1 which does not have neutrons.)
The protons and neutrons make up the nucleus of the atom which is at the center of the atom and around which the electrons revolve.
Protons and electrons are electrically charged with protons having a single positive charge and electrons having a single negative charge. Neutrons are electrically neutral. The mass of protons and neutrons are approximately the same and their sum gives the mass of the atom. Electrons have an extremely low mass and which can be ignored.
The atoms of different elements have differing numbers of constituent particles. The number of protons gives the atomic number of elements. Atoms of the same element can have different numbers of neutrons which changes their atomic mass but not their atomic number. These are called isotopes of the element.
The atom is made up of three parts: protons, neutrons, electrons. The protons and electron are located at the center of the atom; protons having positive charges while electrons having negative charges. The neutrons have no charge and move around the nucleus. x