a an atom of an element that has a different number of neutrons that the standard atom of that element
b the neutrally charged element in the nucleus of an atom
c the positive particle in the nucleus of an atom
d the number of protons an atom has
protons + neutrons in the nucleus of an atom
1. Atomic Mass 2. Neutron 3. Atomic Number 4. Proton 5. Isotope
pls match them up