The chemical behavior of an atom is determined by the number and configuration of its:

• A. nucleons
• B. protons
• C. neutrons
• D. electrons

Answer: (D)

Verified step by step guidance

1. Understand that the chemical behavior of an atom is primarily influenced by how it interacts with other atoms, which depends on the electrons, especially those in the outermost shell (valence electrons).
2. Recall that nucleons (protons and neutrons) make up the nucleus and determine the atom's identity and mass but do not directly affect chemical reactivity.
3. Recognize that protons define the element's atomic number, but the chemical properties depend on the arrangement of electrons around the nucleus.
4. Note that neutrons contribute to isotopes and nuclear stability but have little effect on chemical behavior.
5. Conclude that the number and configuration of electrons, particularly valence electrons, determine how an atom bonds and reacts chemically.