An ionic bond is a type of chemical bond formed through an electrostatic attraction between two oppositely charged ions. Ionic bonds are formed between a cation, which is usually a metal, and an anion, which is usually a nonmetal. A covalent bond involves a pair of electrons being shared between atoms.
Since medals form cations
nonmedals form anions
LightWave. Lightwave forms the most important example of a transverse wave!
I think it's 2 I tried looking it up because I was not sure.