Why is the configuration of electrons in an atom's outer shell important?

• A. It sets the melting point of the element.
• B. It controls the number of protons in the nucleus.
• C. It determines the chemical reactivity and bonding behavior of the atom.
• D. It affects the atomic mass of the element.

Answer: (C)

Verified step by step guidance

1. Understand that the outer shell of an atom is called the valence shell, and the electrons in this shell are called valence electrons.
2. Recognize that valence electrons are the ones involved in chemical reactions and bonding because they can be gained, lost, or shared with other atoms.
3. Know that the number and arrangement of valence electrons determine how an atom interacts with other atoms, influencing its chemical reactivity and the types of bonds it can form.
4. Realize that properties like melting point, atomic mass, and number of protons are influenced by other factors: melting point depends on the type of bonding and structure, atomic mass depends on protons and neutrons, and the number of protons defines the element itself.
5. Therefore, the electron configuration in the outer shell is crucial because it directly controls the chemical behavior and bonding patterns of the atom.