How many electrons are in the outermost energy level of a chloride ion in table salt?
8 valance electrons are a stable structure that allows Chlorine to achieve the same structures as Argon.
The sodium ion in salt has a charge of +1. This is because the electron density of the single valance electron of sodium has been taken for the most part by Chlorine. This give Chlorine 8 electrons.
There are eight electrons in the outermost energy level of a chloride ion.
Chlorine (atomic number 17) is in the third row of the Periodic Table.
We see that it has 7 electrons in its outermost energy level.
It needs only one more electron to give it an octet of electrons and a noble gas configuration.
Hence, a chloride ion has 8 electrons in its outermost energy level.