Which of the following is closest to the atomic mass of copper (Cu)?

• A. 47.87 u
• B. 65.39 u
• C. 63.55 u
• D. 58.93 u

Answer: (C)

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 copper (Cu) has an atomic number of 29, and its atomic mass is typically found on the periodic table as a decimal value reflecting isotope distribution.
3. Compare the given options to the known atomic mass of copper, which is approximately 63.55 u, based on standard periodic table data.
4. Eliminate options that are significantly different from this known value, such as 47.87 u, 65.39 u, and 58.93 u, by considering how close they are to 63.55 u.
5. Conclude that the value closest to the atomic mass of copper is 63.55 u, which matches the accepted atomic mass for copper.