Question

when chlorine gains an electron to become a chloride ion with a -1 charge it ends up with the electron configuration of argon why doesn't it become an argon atom​

Answer 1

Because the identity of an atom is not based on electrons or charge. It’s entirely based on the number of protons the atom has.

Chlorine and only chlorine has 17 protons

Argon and only argon has 18 protons.

Answer 2

Answer:

Only number of electrons of Chlorine and argon are going to be same remaining things like mass,reactivity,ionic radii, and so on will be different so if a chlorine gains a electron we can't call it argon!! chlorine is an diatomic gas, argon exist as monoatomic, chlorine can loose that electron and form bond with another cation in order to remove the charge density,, but argon is stable itself!