Respuesta :
The full valence electron shell is the characteristic of the stable electron configuration. The element, argon (Ar) has a completely filled valence shell. Thus, option D is correct.
What are electron shells?
Electron shells are situated in the atom outside the nucleus where the electrons are present. They are made of groups of orbitals and have subshells in them.
The electron shell is said to be completely filled when the electronic configuration of the atom is such that the last shell has eight complete electrons in them.
In the case of argon, they have a completely filled valence shell as it has atomic number 18 which makes its configuration as, 2, 8, 8. It shows that it follows the octet rule of electronic configuration.
Therefore, argon is a noble gas that has a completely filled valence electron shell.
Learn more about electron shells here:
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