Which of the following primarily determines the chemical properties of an atom?

• A. The atomic mass
• B. The total number of neutrons
• C. The number of electron shells
• D. The number of valence electrons

Answer: (D)

Verified step by step guidance

1. Understand that the chemical properties of an atom are mainly influenced by how it interacts with other atoms, which depends on its electrons, especially those involved in bonding.
2. Recall that electrons are arranged in shells around the nucleus, but not all electrons equally affect chemical behavior; the outermost electrons, called valence electrons, are the key players.
3. Recognize that atomic mass and the number of neutrons affect the atom's mass and stability but do not directly determine chemical reactivity or bonding characteristics.
4. Note that while the number of electron shells affects the size and energy levels of the atom, it is the number of valence electrons that primarily governs how an atom forms chemical bonds.
5. Conclude that the number of valence electrons is the primary factor determining an atom's chemical properties because these electrons participate in chemical reactions and bonding.