Step-by-step explanation:
It is known that for a neutral atom the number of protons present in that atom is equal to the number of electrons present in it.
Also, atomic number means the sum of total number of protons present in an atom.
For example, when a gold atom has net charge 0 then it means it is neutral in nature.
Also, it contains 79 electrons. This also means it contains 79 protons.
Thus, we can conclude that an atom of gold (Au) which has 79 electrons will also contain 79 protons.