Question

.What does the atomic number of an element indicate?

Answer 1

The identity of the element.

Explanation:

The atomic number, `Z`, is the number of protons, massive, positively charged nuclear particles. The number `Z` determines the indentity of the element.

`Z=1`, the element in `H`, `Z=2`, the element in `He`,
`Z=3`, the element in `Li`,........`Z=6`, the element in `C`,
`Z=19`, the element in `K`,......`Z=26`, the element in `Fe`.....

You should not have to remember these, because in every test of chemistry and physics you ever sit, you should be issued a copy of the Perodic Table.