Carbon 14 is an isotope of Carbon-12. What makes Carbon 14 an isotope?

What if there are a different number of Neutrons? Sometimes elements have a different number of neutrons than usual, so therefore have a different atomic mass. This is what we call an Isotope (a variant form of an element which has the same number of protons but a differing number of neutrons). Sometimes we’ll see Isotopes labeled with their new mass like this: 14C = this is Carbon 14. Notice it has a different mass than what is on your periodic table The average mass of all the isotopes is defined as an element’s Atomic Weight. Can you answer questions about these Isotopes? ELEMENT ATOMIC MASS NUMBER OF PROTONS NUMBER OF NEUTRONS 14C A   B   C  15N D   E   F  2H G  H  I  Use your table to look up the number of protons, remember that never changes!

if the 3 to 1 transition has an energy of 1.94x10^-18 J what do you think the energy of the 1 to 3 transition is explain why

what makes Isotopes of an element different from one another?