Argon (ar): [ne]3s23p6 core electrons: __ valence electrons: __

Answer : Core electrons = 10

Valence electrons = 8

Explanation :

Core electrons : They are the electrons in an atom that do not participate in bonding.

Valence electrons : They are electrons in an atom that participate in bonding.

Electronic configuration : It is defined as the representation of electrons around the nucleus of an atom.  

Number of electrons in an atom are determined by the electronic configuration.

The electronic configuration of argon (Ar) will be:

The electronic configuration of neon (Ne) will be:

So, the electronic configuration of argon (Ar) in noble gas notation will be:

In the given electronic configuration of argon, the electrons present in 1st shell and 2nd shell are the core electrons and the electrons present in 3rd shell are the valence electrons. That means,

Number of core electrons = 2 + 2 + 6 = 10

Number of valence electrons = 2 + 6 = 8