# What is the atomic number of an element based on?

Dec 27, 2016

The number of protons a single atom contains in its nucleus in a neutral charge.

#### Explanation:

The number of protons a single atom contains in its nucleus in a neutral charge.

In order to be neutral, the number of protons must equal the number of electrons.

Hope this helps :)

Dec 28, 2016

The atomic number of an element is the number of protons in the nuclei of its atoms. The atomic number is different for each element and determines the identity of an element. The elements are arranged in order of increasing atomic number on the periodic table. The atomic number of an element never changes during a physical or chemical change, but it can change during a nuclear reaction, in which case the element also changes. So far, there are $118$ elements known, with atomic numbers from $1 - 118$. In a neutral atom , the atomic number is equal to the number of electrons.