Which of the following best describes how the inner electron shells of an atom differ from the outer electron shells?

• A. Outer electron shells are always completely filled before inner shells begin to fill.
• B. Inner electron shells contain more electrons than outer electron shells in all atoms.
• C. Inner electron shells are responsible for chemical bonding, while outer shells are not.
• D. Inner electron shells are closer to the nucleus and generally have lower energy than outer electron shells.

Answer: (D)

Verified step by step guidance

1. Understand the structure of an atom: electrons are arranged in shells or energy levels around the nucleus, with inner shells being closer to the nucleus and outer shells farther away.
2. Recall that inner electron shells are generally lower in energy because they are more strongly attracted to the positively charged nucleus due to their proximity.
3. Recognize that outer electron shells (valence shells) are involved in chemical bonding because they contain the electrons that can be gained, lost, or shared during reactions.
4. Note that inner shells are usually filled before outer shells begin to fill, but outer shells are not always completely filled; this depends on the element and its electron configuration.
5. Conclude that the key difference is that inner electron shells are closer to the nucleus and have lower energy, while outer shells are higher in energy and participate in chemical bonding.