Question

what do carbon - 12 and carbon - 14 have in common? they have the same number of neutrons they have the same atomic weight they have same number of protons they have the same atomic mass

Explanation:

Carbon - 12 and carbon - 14 are isotopes of carbon. Isotopes of an element have the same number of protons (which defines the element). The number of neutrons is different (for carbon - 12, neutrons \(n = 12 - 6=6\); for carbon - 14, \(n = 14 - 6 = 8\)). Atomic weight (or atomic mass) is different (\(12\) for carbon - 12 and \(14\) for carbon - 14).

Answer:

They have same number of protons.