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

• A. The total number of neutrons
• B. The number of valence electrons
• C. The number of energy levels
• D. The atomic mass

Answer: (B)

Verified step by step guidance

1. Understand that an atom's chemical properties are mainly influenced by how it interacts with other atoms, which depends on the electrons involved in bonding.
2. Recall that electrons are arranged in energy levels (shells) around the nucleus, but not all electrons equally affect chemical behavior.
3. Identify that valence electrons are the electrons in the outermost energy level of an atom and are responsible for forming chemical bonds.
4. Recognize that the total number of neutrons affects the isotope of the element but does not significantly influence chemical properties.
5. Conclude that the number of valence electrons primarily determines an atom's chemical properties because they dictate how the atom bonds and reacts chemically.