A nonmetal is an element that tends to be dull, brittle, and a poor conductor of heat and electricity.
nonmetal
If by "pair atoms" you mean molecules, and by potassium and oxygen you mean potassium oxide, then molecules can not be described as metals or nonmentals. Potassium is a metal, while oxygen is nonmetal.
Nails are metal.
nonmetal
nonmetal
FeO is not a nonmetal; it is a compound composed of iron (a metal) and oxygen (a nonmetal).
Fluoride is the ion of fluorine, which is a nonmetal.
Diamond is carbon which is a nonmetal
Nonmetal
Sulfur is a nonmetal.
nonmetal
Sulfur powder is a nonmetal. It is a chemical element with the atomic number 16 and is classified as a nonmetal on the periodic table.