Which of the following is a factor in determining the average atomic mass of an element?

• A. The atomic number of the element
• B. The melting point of the element
• C. The number of valence electrons
• D. The relative abundance of each isotope

Answer: (D)

Verified step by step guidance

1. Understand that the average atomic mass of an element is calculated based on the masses of its isotopes and their relative abundances in nature.
2. Recall that isotopes are atoms of the same element with different numbers of neutrons, resulting in different masses.
3. Recognize that the atomic number (number of protons) is the same for all isotopes of an element and does not affect the average atomic mass calculation directly.
4. Note that physical properties like melting point or the number of valence electrons do not influence the average atomic mass because they do not relate to isotope mass or abundance.
5. Conclude that the key factor in determining the average atomic mass is the relative abundance of each isotope, as it weights the contribution of each isotope's mass to the overall average.