Collective Names of Like Elements (Shown on Periodic Table)
The following collective names for like elements are IUPAC-approved:
alkali metals (Li, Na, K, Rb, Cs, Fr),
alkaline earth metals (Be, Mg, Ca, Sr, Ba, Ra),
pnictogens (N, P, As, Sb, Bi),
chalcogens (O, S, Se, Te, Po),
halogens (F, Cl, Br, I, At),
noble gases (He, Ne, Ar, Kr, Xe, Rn),
lanthanoids (La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu),
rare earth metals (Sc, Y and the lanthanoids) and
actinoids (Ac, Th, Pa, U, Np, Pu, Am, Cm, Bk, Cf, Es, Fm, Md, No, Lr)
(Nomenclature of Inorganic Chemistry, IUPAC Recommendations 2005).
Although lanthanoid means ‘like lanthanum’ and so should not include lanthanum, lanthanum has become included by common usage. Similarly, actinoid. The ending ‘ide’ normally indicates a negative ion, and therefore lanthanoid and actinoid are preferred to lanthanide and actinide (Nomenclature of Inorganic Chemistry, IUPAC Recommendations 2005).
Optionally, the letters s, p, d and f may be used to distinguish different blocks of elements. For example, the elements of groups 3–12 are the d-block elements.
Other collective names also exist for elements with common specific properties. For example, a precious metal is a rare, naturally occurring metallic chemical element of high economic value like gold, silver, platinum and palladium.