How many protons are in an element with an atomic number of eight and a mass number of 18

The Atomic Number is the number of protons in the nucleus of an atom.

If the Atomic Number is 8, then there are 8 protons in the nucleus of

each atom.

The rest of the Atomic Mass comes from neutrons in the nucleus.

I don't know if there's such an atom that's stable with mass of 18

of which 8 of them are protons. If there is, then it has 10 neutrons

in the nucleus of each atom.