Which of the following pairs represent isotopes?

• A. 8^16O and 8^16O
• B. 1^1H and 2^4He
• C. 11^23Na and 12^24Mg
• D. 6^12C and 6^14C

Answer: (D)

Verified step by step guidance

1. Recall that isotopes are atoms of the same element that have the same atomic number (number of protons) but different mass numbers (sum of protons and neutrons).
2. Identify the atomic number (the lower left number) and the mass number (the upper left number) for each pair of atoms given.
3. Compare the atomic numbers in each pair to check if they are the same, which means they are the same element.
4. For pairs with the same atomic number, check if their mass numbers are different; if yes, then those pairs are isotopes.
5. Apply this to the pair 6^12C and 6^14C: both have atomic number 6 (carbon), but different mass numbers (12 and 14), confirming they are isotopes.