Humber Admissions Practice Test

Which of the following is true about valence shells?

1. They are filled first during electron configuration

2. They are the outermost shells that interact in bonding

3. They contain only neutrons

4. They have the lowest energy level

The correct answer is: They are the outermost shells that interact in bonding

Valence shells refer to the outermost electron shells of an atom and play a crucial role in chemical bonding and reactions. The correct statement highlights that valence shells are indeed the outermost shells where the electrons reside that are available for bonding with other atoms. These electrons, known as valence electrons, determine how an atom interacts with its environment, including the types of bonds it can form, whether ionic or covalent, and how it reacts chemically. The other statements do not accurately represent the properties of valence shells. For instance, while electron configuration involves filling various shells in a specific order based on energy levels, the valence shell is not necessarily filled first. Additionally, valence shells contain electrons, not neutrons, which are found in the nucleus of the atom. Lastly, valence shells do not always have the lowest energy levels; in fact, they can have higher energy compared to the inner shells, especially in larger atoms where the valence shell is further from the nucleus. Thus, the focus on interaction in bonding is what makes the correct statement true in relation to valence shells.