How do you calculate the atomic number of an element?

Atomic number of an element: The atomic number of an element can be calculated by adding the total number of protons which is also equal to the total number of electrons in a neutral atom.

For a neutral atom: Atomic number = Number of protons = Number of electrons

For an ion: Atomic number = Number of protons = Number of electrons + Charge on atom

Example: A sodium atom has 11 protons and 11 electrons which also denotes It has 11 positive charges and 11 negative charges.

So, its atomic number can be calculated as = Number of protons = Number of electrons = 11.

Hence, the atomic number of an element can be calculated by calculating the total number of protons or electrons of an element.