Understanding Ionic Compounds
Ionic compounds form when a metal (typically) loses electrons to become a positively charged ion (cation) and a nonmetal gains those electrons to become a negatively charged ion (anion). The opposite charges then attract, holding the compound together.
Let's analyze each element:
* Iodine (I): Iodine is a nonmetal. While it can form anionic compounds, it's more likely to form covalent bonds with other nonmetals.
* Cesium (Cs): Cesium is a metal. It readily loses an electron to become a +1 cation (Cs+).
* Helium (He): Helium is a noble gas. It has a full outer shell of electrons and is extremely unreactive. It will not easily gain or lose electrons.
The Answer
Cesium (Cs) will form an ionic compound with chlorine (Cl). The reaction would be:
Cs + Cl -> CsCl
* Cesium will lose one electron to become a Cs+ cation.
* Chlorine will gain one electron to become a Cl- anion.
* The opposite charges will attract, forming the ionic compound cesium chloride (CsCl).
