Answer:
Cations are ions that are positively charged. They form when they lose an electron because they would have more protons than electrons. In your problem you have for example potassium (number three).
Iodine is a cation because it lost one electron. The ion symbol then would be:
I ⁺
So this is your clue. If it has a positive or a plus sign on top, that would make it a cation. Another clue would be if it LOST an electron, then it is a cation.
An anion, on the other hand, is negatively charged, because they gain electrons, making the electrons more than the protons. In your problem, you have Iodine as an example (number one).
Iodine gained one electron and the ion symbol would be:
I⁻
So again that is your clue for anions, they have a negative or a minus sign on top of the symbol. If they GAINED an electron, that would make them an anion.
Naming monoatomic anions is easy. They are named with the suffix -ide at the end. (Cations retain their name). For example Sulfur (number two).
Sulfur is an anion that gained two electrons with an ion symbol of:
S²⁻
So from the name <u>Sulfur</u><u> </u>the name will change into "Sulfide" and its name will now be <u>Sulfide ion. </u>