What is the electron configuration for a chloride ion?

1 Answer
Dec 31, 2015

#1"s"^2 2"s"^2 2"p"^6 3"s"^2 3"p"^6#

OR

#"[Ne]" 3"s"^2 3"p"^6#

Explanation:

The electron configuration of a chlorine atom (#"Cl"#) is as follows:

#1"s"^2 2"s"^2 2"p"^6 3"s"^2 3"p"^5#

But a chlorine ion (#"Cl"^-#) has acquired a #"(1)-"# charge as a result of gaining 1 electron. Thus, its electron configuration is:

#1"s"^2 2"s"^2 2"p"^6 3"s"^2 3"p"^6#

This may also be expressed as:

#"[Ne]" 3"s"^2 3"p"^6#