Answer:
The answer is D. The energy possessed by an electron at a set distance from the nucleus.
Explanation:
Energy levels (also called electron shells) are fixed distances from the nucleus of an atom where electrons may be found. Electrons are tiny, negatively charged particles in an atom that move around the positive nucleus at the center.
Energy levels are the fixed amount of energy that a system described by quantum mechanics, such as a molecule, atom, electron, or nucleus, can have.
