"Which of the following sets represents a pair of isotopes"? how to i figure that out if they are giving me answers such as
14C and 14N
206Pb and 208Pb
ect... i dont want the answer i just need help understanding

Question

"Which of the following sets represents a pair of isotopes"? how to i figure that out if they are giving me answers such as
14C and 14N 
206Pb and 208Pb
ect... i dont want the answer i just need help understanding

aaronq · Answer

isotopes are atoms with the same identity (same number of protons) that vary in the number of neutrons. So an isotope of carbon is always a carbon atom (6 protons), carbon and nitrogen cannot be isotopes because they differ in number of protons.