AFOQT Practice Test

What are the outer shell electrons of an atom called?

1. Core electrons

2. Valence electrons

3. Free electrons

4. Conduction electrons

The correct answer is: Valence electrons

The outer shell electrons of an atom are referred to as valence electrons. These electrons are located in the outermost energy level of an atom and play a crucial role in chemical bonding and reactivity. Valence electrons determine how an atom interacts with other atoms, including the types of bonds it can form (such as ionic or covalent bonds). Understanding that valence electrons are responsible for an atom's chemical properties is fundamental in chemistry. For instance, elements with the same number of valence electrons typically exhibit similar reactivity and bonding behavior, which is why the periodic table groups elements accordingly. In contrast, core electrons are the electrons that are found in the inner shells closer to the nucleus. These core electrons do not participate in bonding and are instead responsible for shielding the nucleus from the outer valence electrons. Free electrons and conduction electrons refer to electrons that can move freely in conductive materials; they are more relevant in discussions about electrical conductivity rather than atomic structure.