Which property of an atom primarily determines the types of chemical reactions it can participate in?

• A. The number of valence electrons
• B. The number of neutrons
• C. The total number of protons and electrons
• D. The atomic mass

Answer: (A)

Verified step by step guidance

1. Understand that chemical reactions involve the making and breaking of bonds between atoms, which depends on the electrons involved in bonding.
2. Recall that electrons in an atom are arranged in energy levels or shells, with the outermost shell called the valence shell.
3. Recognize that the number of valence electrons (electrons in the outermost shell) determines how an atom interacts with other atoms, influencing its chemical reactivity.
4. Note that neutrons affect atomic mass but do not influence chemical reactions directly, and the total number of protons and electrons defines the element but not its reactivity pattern specifically.
5. Conclude that the primary property determining the types of chemical reactions an atom can participate in is the number of valence electrons.