The Atomic Number (Z) corresponds to the number of protons (p+) that an atom has in its nucleus.
When atoms are neutral, the number of protons (p+) coincides with the number of electrons (e–).
To represent the atomic number (Z) and the mass number (A) of a chemical element, it is written down:
The chemical identity of an atom is determined by its atomic number. For example, the atomic number of nitrogen is 7. This means that each neutral atom of nitrogen has 7 protons and 7 electrons. Or, looked at another way, every atom in the universe that contains 7 protons is called “Nitrogen”.
