Which number on the periodic table represents the atomic mass of an element?

• A. The whole number above the element symbol
• B. The group number of the element
• C. The number of electrons in a neutral atom
• D. The number below the element symbol, usually with a decimal

Answer: (D)

Verified step by step guidance

1. Understand that the periodic table displays several key numbers for each element: the atomic number, the atomic mass, and sometimes the group number.
2. Recall that the atomic number is the whole number above the element symbol and represents the number of protons (and electrons in a neutral atom).
3. Recognize that the group number refers to the column of the element in the periodic table and is not directly related to atomic mass.
4. Know that the atomic mass is typically the number below the element symbol and is often a decimal because it represents the weighted average mass of all isotopes of that element.
5. Therefore, the atomic mass is the number below the element symbol, usually with a decimal, which reflects the average mass of the element's atoms.