what are its applications in common?
They do not have any universal or near-universal applications.
Nonmetal
do not have any universal or near-universal applications. 
what is metalloid? It is a type of chemical element. what are the isotopes of this element? UNANSWERABLE what is its description? It is a  mixture of metals and nonmetals. what are the properties of the latter mentioned? Physically, they largely exist as diatomic or monatomic gases while chemically they mostly have high ionisation energies. what are its alternative categories? The relative homogeneity of the halogens, physical form, electronegativity etc what are its data source? CRC Handbook of Physics and Chemistry;" standard electrode potentials
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Nonmetal [SEP] Applications in common
Nonmetals do not have any universal or near-universal applications. This is not the case with metals, most of which have structural uses; nor the metalloids, the typical uses of which extend to (for example) oxide glasses, alloying components, and semiconductors. Shared applications of different subsets of the nonmetals instead encompass their presence in, or specific uses in the fields of "cryogenics and refrigerants": H, He, N, O, F and Ne; "fertilisers": H, N, P, S, Cl (as a micronutrient) and Se; "household accoutrements": H (primary constituent of water), He (party balloons), C (in pencils, as graphite), N (beer widgets), O (as peroxide, in detergents), F (as fluoride, in toothpaste), Ne (lighting), P (matches), S (garden treatments), Cl (bleach constituent), Ar (insulated windows), Se (glass; solar cells), Br (as bromide, for purification of spa water), Kr (energy saving fluorescent lamps), I (in antiseptic solutions), Xe (in plasma TV display cells, a technology subsequently made redundant by low cost OLED displays), while Rn also sometimes occurs, but then as an unwanted, potentially hazardous indoor pollutant; "industrial acids": C, N, F, P, S and Cl; "inert air replacements": N, Ne, S (in sulfur hexafluoride SF), Ar, Kr and Xe; "lasers and lighting": He, C (in carbon dioxide lasers, CO), N, O (in a chemical oxygen iodine laser), F (in a hydrogen fluoride laser, HF), Ne, S (in a sulfur lamp), Ar, Kr and Xe; and "medicine and pharmaceuticals": He, O, F, Cl, Br, I, Xe and Rn.