An electrically neutral atom has an equal number of protons and electrons
Example: Oxygen contains 8 protons. There fore its atomic number is 8 in its nuetral atom, the number of electrons is also 8 oxygen structure-👉
NOTE: The atom of an element has a characteristic number of protons in its nucleus, which distinguishes it from the atom of the other elements. The atomic number of an element never varies and it is a fixed value for a particular element.
Isotopes Some atoms of the same element have same atomic number these atoms are called isotopes. Exaple of isotopes: hydrogen 👉