Written by the Fiveable Content Team • Last updated September 2025
Verified for the 2026 exam
Verified for the 2026 exam•Written by the Fiveable Content Team • Last updated September 2025
Definition
Electron shells are energy levels where electrons reside around an atom's nucleus. Each shell can hold a certain number of electrons.
Related terms
Valence Electrons: These are electrons in the outermost shell of an atom that participate in chemical reactions.
Atomic Orbital: A region of space around the nucleus where an electron is likely to be found.
Quantum Mechanics: The branch of physics dealing with atomic and subatomic systems, providing mathematical descriptions for their dual particle-like and wave-like behavior. It explains why electron shells exist as they do.