Which of the following properties of an element are most directly affected by the distribution of its electrons?

• A. Chemical reactivity
• B. Number of protons
• C. Melting point
• D. Atomic mass

Answer: (A)

Verified step by step guidance

1. Understand that the distribution of electrons in an element refers to how electrons are arranged in its atomic orbitals, especially the outermost or valence electrons.
2. Recall that chemical reactivity depends largely on the valence electrons because these electrons participate in forming chemical bonds with other atoms.
3. Recognize that the number of protons (atomic number) is fixed for each element and does not change with electron distribution; it defines the element itself.
4. Note that melting point is a physical property influenced by the type of bonding and structure in the solid state, which is indirectly related to electron distribution but not as directly as chemical reactivity.
5. Understand that atomic mass depends on the number of protons and neutrons in the nucleus and is not affected by how electrons are distributed.