What is the chemical symbols for these ions? And how do I figure that out?

Question

A chlorine atom that has gained one electron

an oxygen atom that has gained two electrons

a cesium atom that has lost one electron

a aluminum atom that has lost three electrons

Answer 1

Chlorine is neutral. Electrons have a -1 charge. Gaining one electron makes Cl^-

Oxygen atom is neutral. Gaining 2 electrons makes O^2-

Cesium atom is neutral. Losing one electron makes Cs⁺

Aluminum atom is neutral. Losing 3 electrons makes Al³⁺