Which of the following are the stable isotopes of nitrogen?

• A. N-15 and N-16
• B. N-13 and N-14
• C. N-14 and N-15
• D. N-12 and N-15

Answer: (C)

Verified step by step guidance

1. Understand that isotopes of an element have the same number of protons but different numbers of neutrons, and stability depends on the neutron-to-proton ratio and nuclear forces.
2. Recall that nitrogen has an atomic number of 7, meaning every nitrogen isotope has 7 protons.
3. Identify the isotopes listed and their neutron numbers by subtracting the atomic number (7) from the mass number: for example, N-14 has 14 - 7 = 7 neutrons.
4. Recognize that stable isotopes of nitrogen are those that do not undergo radioactive decay under normal conditions; N-14 and N-15 are known stable isotopes.
5. Conclude that isotopes like N-12, N-13, and N-16 are unstable because they have neutron-to-proton ratios that lead to radioactive decay, so the stable isotopes are N-14 and N-15.