Question

which of the following represents a pair of isotopes? fe+2, fe+3 option 3 ca+2,be+2 option 1 7n, 8o option 4 12c, 14c option 2

Explanation:

Isotopes are atoms of the same element with different mass - numbers (same atomic number, different number of neutrons). In the case of $^{12}C$ and $^{14}C$, they are both carbon atoms (same atomic number, 6), but have different mass numbers (12 and 14 respectively). Option 1 has different elements (Ca and Be), Option 3 has different ions of iron with different charges, and Option 4 has different elements (N and O).

Answer:

Option 2. $^{12}C$, $^{14}C$