Amongst this diversity, scientists have found it useful to apply names for various sets of elements that have similar properties, to varying degrees.
Many of these sets are formally recognized by the standards body IUPAC.
[1] The following collective names are recommended or noted by IUPAC: Another common classification is by degree of metallic or nonmetallic behaviour and characteristics.
Elements in the vicinity of where the metals and nonmetals meet are sometime classified as metalloids or an equivalent term.
These two to three classes are commonly marked by differing background colors in the periodic table.