Which of the following is the atomic mass of cobalt (Co)?

• A. 65.39 u
• B. 58.93 u
• C. 55.85 u
• D. 63.55 u

Answer: (B)

Verified step by step guidance

1. Understand that the atomic mass of an element is the weighted average mass of all the naturally occurring isotopes of that element, measured in atomic mass units (u).
2. Recall that the atomic mass is typically found on the periodic table and represents the average mass of the element's atoms, not just a single isotope.
3. Identify cobalt (Co) on the periodic table to find its atomic mass value, which is usually listed below the element symbol.
4. Compare the given options to the known atomic mass of cobalt from the periodic table, which is approximately 58.93 u.
5. Select the value closest to the known atomic mass of cobalt, confirming that 58.93 u is the correct atomic mass.