Explanation:
1 mol of an atom (irregardless of the element) contains the Avogadro's number of atoms. This is given as;
1 mol = 6.022 * 10^23 atoms
For a neutral atom;
NUmber of protons = Number of electrons
The relationship between proton and neutron is given as;
Mass Number = Protons + Neutrons
Ag-108
Atoms = 6.022 * 10^23 atoms
Protons = Atomic Number = 47
Electrons = 47
Neutrons = Mass Number - Protons = 108 - 47 = 61
Pt-195
Atoms = 6.022 * 10^23 atoms
Protons = Atomic Number = 78
Electrons = 78
Neutrons = Mass Number - Protons = 195 - 78 = 117
