How can you determine the number of protons electrons and neutrons in an elements atoms?
Consult the periodic table of elements to learn the element’s atomic number, which is the number of protons in each atom of that element. The number of electrons will be the same. From the table, also note the atomic weight. That is the total weighted average number of protons and neutrons in atoms of that element. Subtract the number of protons from the atomic weight to get the weighted average number of neutrons in atoms of that element. Even though all atoms of a given element will have the same number of protons, they will have varying numbers of neutrons over a small range; these are called isotopes. Isotopes of an element will have their own natural abundances, leading to non-integer atomic weights even though each individual atom must have an integer as the total number of protons and neutrons in its nucleus.
