Which of the following is closest to the atomic mass of oxygen?

• A. 16.00 u
• B. 12.01 u
• C. 1.008 u
• D. 32.07 u

Answer: (A)

Verified step by step guidance

1. Understand that the atomic mass of an element is the weighted average mass of all its naturally occurring isotopes, measured in atomic mass units (u).
2. Recall that oxygen's atomic mass is based primarily on its most common isotope, oxygen-16, which has an atomic mass close to 16 u.
3. Compare the given options to the known atomic masses of common elements: 12.01 u corresponds to carbon, 1.008 u corresponds to hydrogen, and 32.07 u corresponds to sulfur.
4. Identify that the value closest to oxygen's atomic mass is 16.00 u, which matches the mass of oxygen-16 isotope.
5. Conclude that the correct choice is 16.00 u because it best represents the atomic mass of oxygen.