What is the atomic mass of sodium (Na) as listed on the periodic table?

• A. 22.99
• B. 12.01
• C. 28.09
• D. 35.45

Answer: (A)

Verified step by step guidance

1. Understand that the atomic mass of an element listed on the periodic table represents the weighted average mass of all naturally occurring isotopes of that element, measured in atomic mass units (amu).
2. Locate sodium (Na) on the periodic table, which is in group 1 and period 3, to find its atomic mass value.
3. Identify the atomic mass number given for sodium, which is typically displayed below the element symbol on the periodic table.
4. Recognize that the atomic mass of sodium is approximately 22.99 amu, reflecting the average mass of its isotopes weighted by their natural abundance.
5. Compare this value to the other options provided (12.01, 28.09, 35.45) and confirm that 22.99 is the correct atomic mass for sodium.