Is it possible for the number of atoms of different elements to have the same mass number?

Answer 1

Atoms of different elements can have the same mass. An isotope of nitrogen with 7 protons and 9 neutrons, for example, will have the same mass as an isotope of oxygen with 8 protons and 8 neutrons.

Each element will have a unique number of protons, but the number of neutrons can be varied. Thus, two atoms can have the same mass (dictated by the neutrons + protons) but still be different elements (dictated by the number of protons alone).

Answer 2

Yes, often, though these "isotopes" are usually radioactive. The mass number is the sum of the protons and neutrons within the nucleus. Some stable isotopes have the same Atomic Mass as other elements.

http://ie.lbl.gov/education/isotopes.htm Cadmium 110 and Palladium 110 are both stable isotopes of each element. Silver (Ag) is stable for 107 and 109, but not for any other mass number. Rhenium is stable for 103, but mass 106 has a half life of 30 seconds. Cadmium 106, 108, 110, 111, 112, 114, and 116 are all stable. This makes me wonder which element has the most stable number of isotopes.

Answer 3

Yes, there are elements which have isotopes, i.e same atomic number & different atomic weight, so atoms f different elements can have same atomic weights.