Kaplan Nursing Entrance Practice Exam

What is a key feature of valence electrons?

1. They determine an atom's chemical properties.

2. They are found in the innermost shell.

3. They are not involved in bonding.

4. They are always equal to the number of protons.

The correct answer is: They determine an atom's chemical properties.

Valence electrons are crucial in determining an atom's chemical properties because they are the electrons that reside in the outermost shell of an atom. These electrons play a vital role in how an atom interacts with others, influencing its ability to form bonds, react with other substances, and determine the overall reactivity and stability of the atom. The behavior and characteristics of valence electrons dictate the types of chemical bonds an atom can form, whether ionic or covalent, as well as its placement in the periodic table, which is intrinsically linked to its chemical properties. The other options do not correctly reflect the significance of valence electrons. For instance, they are not found in the innermost shell since valence electrons are specifically those located in the outermost shell. They are also heavily involved in bonding processes rather than being excluded from them. Lastly, the number of valence electrons does not always equate to the number of protons; for some elements, especially in charged states or isotopes, these numbers can vary significantly.