K-shell

[key-shel]

noun

Physics.

1. the first shell of electrons surrounding the nucleus of an atom and containing, when filled, two electrons having principal quantum number 1.

Word History and Origins

Origin of K-shell¹

First recorded in 1965–70

Example Sentences

However, because the K-shell transition lines of chromium and manganese are weak and those of iron and nickel are very close in photon energy, high-resolution spectroscopy is required for an accurate determination of the abundances of these elements.

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