Chemistry - Electron arrangements
We consider Bohr's major energy levels (stationary states) to be the
major energy divisions around the nucleus of an atom. They are commonly
The electron shells are labelled K, L, M, N, O, etc. or 1, 2, 3, 4, 5 etc.
The shell capacity is determined by 2n where n is the shell number.
The first (K) shell holds up to two electrons.
The second (L) shell holds up to eight electrons.
The third (M) shell holds up to 18 electrons.
The fourth (N) shell holds up to 32 electrons.
Shell electron arrangements are written in order from the innermost shell
(i.e. the one closest to the nucleus) to the outermost.
Writing shell electron arrangements is a simple process for the first 20
elements, but variations in energy levels become significant as the shells
occupy more space around the nucleus.
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