Shell
Definition and meaning of Shell in chemistry.
A shell is a specific grouping of electrons surrounding the nucleus of an atom that share the same principal quantum number. It represents the primary, quantized energy level of an electron in atomic structure models.
In more detail
Electron shells are scientifically designated by the principal quantum number n, which can take integer values like 1, 2, 3, and so on, or they are denoted by the historical alphabetical letters K, L, M, and N. The farther a given electron shell is from the central atomic nucleus, the higher its baseline energy level and the greater the total number of electrons it can theoretically hold. Each distinct shell is further physically divided into various subshells, such as s, p, d, and f, which contain the specific geometric orbitals where electrons are most likely to be located at any given moment.
Key facts
| Field | Physical Chemistry |
|---|---|
| Maximum capacity | 2n^2 electrons per shell |
| Notation | K, L, M, N or n=1, 2, 3, 4 |
The n=2 shell, also known as the L shell, of an oxygen atom holds a total of six valence electrons, which are split precisely between the 2s and 2p subshells.
Frequently asked questions
How many electrons can the first energy shell hold?
The first shell, or K shell, can hold a maximum of exactly 2 electrons in its single 1s orbital.