The atomic number is the number of protons in the nucleus.
The overall charge of an atom is zero. This is because an atom has the same number of electrons as protons.Protons and neutrons are held together in the nucleus by the strong nuclear force. Most atoms contain approximately the same number of neutrons and protons. As the nucleus gets bigger, more neutrons are needed to hold the neutrons and protons together.The number of protons in the atom of an element is unique and identifies the element. There are 118 known elements and therefore 118 different types of atom. The atomic number of an element is the number of protons in the nucleus. The atomic number is different for each element and identifies the element.The periodic table lists the elements in order of atomic number.