What is the charge of a chlorine ion that has
gained 1 electron?

Heyo!

Explanation:

If you add an electron, as is the case with chlorine, you upset the balance between the positive and negative charges. There are 18 electrons and 17 protons, so the chlorine atom has become a charged chlorine ion with a charge of negative one (-1).

Hope This Helps Amigo! From, Adam :)

- decrease the number of plants and animals living in the water.