Which of the following is closest to the atomic mass of aluminum (Al)?

• A. 12.01 u
• B. 35.45 u
• C. 26.98 u
• D. 55.85 u

Answer: (C)

Verified step by step guidance

1. Understand that the atomic mass of an element is the weighted average mass of all the isotopes of that element, measured in atomic mass units (u).
2. Recall that aluminum (Al) is a specific element on the periodic table with a characteristic atomic mass.
3. Identify the atomic masses given in the options: 12.01 u, 35.45 u, 26.98 u, and 55.85 u, and recognize which elements these masses correspond to (for example, 12.01 u is close to carbon, 35.45 u to chlorine, 55.85 u to iron).
4. Compare these values to the known atomic mass of aluminum, which is approximately 26.98 u, based on its position in the periodic table and its isotopic composition.
5. Select the value closest to 26.98 u as the atomic mass of aluminum.