How many neutrons are in an atom of mg-25?
In the atom of Magnesium 25, , there are 12 protons as the proton number is always equal to the atomic number. The molecular mass of Magnesium is 25. The neutron number is given by the formula Molecular mass- Proton number : 25-12=13. So, the neutron number is the magnesium atom is 13.