One of the major energy levels of an atom principal energy level. A principal energy level is the region around an atom's nucleus where electrons are likely to be found, with each level indicating a different distance from the nucleus and energy.
Principal Energy Level: One of the major energy levels of an atom principal energy level. A principal energy level is the region around an atom's nucleus where electrons are likely to be found, with each level indicating a different distance from the nucleus and energy.
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