Which of the following best describes the significance of valence electrons in an atom?

• A. Valence electrons have no effect on the formation of chemical compounds.
• B. Valence electrons determine the chemical reactivity and bonding behavior of an element.
• C. Valence electrons are always found in the innermost electron shell.
• D. Valence electrons are responsible for the atomic mass of an element.

Answer: (B)

Verified step by step guidance

1. Understand that valence electrons are the electrons located in the outermost electron shell of an atom.
2. Recognize that these valence electrons are the ones involved in forming chemical bonds with other atoms.
3. Recall that the number and arrangement of valence electrons determine how an element reacts chemically and what types of bonds it can form.
4. Note that valence electrons do not contribute significantly to atomic mass, which is mostly due to protons and neutrons in the nucleus.
5. Conclude that the correct description is that valence electrons determine the chemical reactivity and bonding behavior of an element.