Question

Question #fab79

Answer 1

The atomic number of an element= number of protons

Explanation:

If you have an element `""_2^4 He`
where 2= atomic number
4= mass number

Adding a proton changes the atomic number, the mass number, basically the entire element.

`""_3^7 Li`
where 3= atomic number
7= mass number

Or if you lower the atomic number (proton number) by 1
`""_1^1 H`
1= atomic number
1= mass number

Hope this helps!