PLEASE HELP. Which element does not form a stable ion with the same electronic structure as argon?
A aluminium
B chlorine
C phosphorus
D potassium

the answer is A, but i chose D. i just need to know why is it wrong. thanks!​

Respuesta :

Explanation:

K+ ion has 18 electrons and Argon also has 18 electrons so they do have the same electronic structure.

However, Al3+ ion has 10 electrons and Argon has 18 electrons, so they do not have the same electronic structure.