electron shell
Technical term in physics and chemistry for the region around an atomic nucleus where electrons are most likely to be found.
Atomic electron shells include the K shell, L shell, M shell, and so on.
The arrangement of electron shells is involved in chemical reactions.
原子核 is the atomic nucleus at the center, while 電子殻 is the surrounding region where electrons exist.
Compound of 電子 (electron) and 殻 (shell), a calque of the English term 'electron shell'.