K-shell

American  

[key-shel] / ˈkeɪˌʃɛl /

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.

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Etymology

Origin of K-shell

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.

From Nature