An emitted gamma ray from any type of excited state may transfer its energy directly to any electrons, but most probably to one of the K shell electrons of the atom, causing it to be ejected from that atom, in a process generally termed the photoelectric effect ( external gamma rays and ultraviolet rays may also cause this effect ).
12.
Therefore, the K shell, which contains only an subshell, can hold up to 2 electrons; the L shell, which contains an and a, can hold up to 2 + 6 = 8 electrons, and so forth; in general, the " n " th shell can hold up to 2 " n " 2 electrons.
13.
When later quantum theory essentially also recovered Bohr's formula for energy of spectral lines, Moseley's law became incorporated into the full quantum mechanical view of the atom, including the role of the single "'1s "'electron which remains in the K shell of all atoms after another K electron is ejected, according to the Schr�dinger equation prediction.
14.
There are a few radionuclides in which the decay energy is not sufficient to convert ( eject ) a 1s ( K shell ) electron, and these nuclides, to decay by internal conversion, must decay by ejecting electrons from the L or M or N shells ( i . e ., by ejecting 2s, 3s, or 4s electrons ) as these binding energies are lower.
