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

• A. 9.01
• B. 12.01
• C. 1.01
• D. 6.94

Answer: (D)

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 (amu).
2. Recall that lithium (Li) is an element with atomic number 3, meaning it has 3 protons, and its atomic mass is typically around 6.94 amu.
3. Compare the given options (9.01, 12.01, 1.01) to the known atomic masses of common elements: 9.01 is close to fluorine, 12.01 is close to carbon, and 1.01 is close to hydrogen.
4. Recognize that none of the options exactly match lithium's atomic mass, but 6.94 is closest to lithium's actual atomic mass, which is not listed among the options but is given as the correct answer.
5. Conclude that the atomic mass closest to lithium's true atomic mass is 6.94, which reflects the weighted average of its isotopes and is the accepted standard value.