Knowing the atomic mass of an element allows inferences about which of the following?

• A. The chemical reactivity of the element
• B. The number of electrons in the outermost shell
• C. The color of the element in its solid state
• D. The average number of protons and neutrons in the atoms of that element

Answer: (D)

Verified step by step guidance

1. Understand that the atomic mass of an element represents the average mass of all the isotopes of that element, weighted by their natural abundance.
2. Recall that atomic mass is approximately the sum of the number of protons and neutrons in the nucleus of an atom, since electrons have negligible mass.
3. Recognize that the atomic number (not atomic mass) determines the number of protons and, in a neutral atom, also the number of electrons, including those in the outermost shell.
4. Note that chemical reactivity depends mainly on the arrangement of electrons, especially the outermost shell, which is not directly given by atomic mass.
5. Understand that physical properties like color in the solid state depend on electron interactions and crystal structure, which are not directly inferred from atomic mass.