HYDROGEN
hydrogen, atomic number
(noun) a nonmetallic univalent element that is normally a colorless and odorless highly flammable diatomic gas; the simplest and lightest and most abundant element in the universe
Source: WordNet® 3.1
Etymology
Noun
hydrogen (countable and uncountable, plural hydrogens)
The lightest chemical element (symbol H), with an atomic number of 1 and atomic weight of 1.00794.
Molecular hydrogen (H2), a colourless, odourless and flammable gas at room temperature.
An atom of the element.
A sample of the element.
Synonyms
• waterstuff
• E949 when used as a packaging agent
Hyponyms
• deuterium
• protium
• tritium
Source: Wiktionary
Hy"dro*gen, n. Etym: [Hydro-, 1 + -gen: cf. F. hydrogène. So called
because water is generated by its combustion. See Hydra.] (Chem.)
Definition: A gaseous element, colorless, tasteless, and odorless, the
lightest known substance, being fourteen and a half times lighter
than air (hence its use in filling balloons), and over eleven
thousand times lighter than water. It is very abundant, being an
ingredient of water and of many other substances, especially those of
animal or vegetable origin. It may by produced in many ways, but is
chiefly obtained by the action of acids (as sulphuric) on metals, as
zinc, iron, etc. It is very inflammable, and is an ingredient of coal
gas and water gas. It is standard of chemical equivalents or
combining weights, and also of valence, being the typical monad.
Symbol H. Atomic weight 1.
Note: Although a gas, hydrogen is chemically similar to the metals in
its nature, having the properties of a weak base. It is, in all
acids, the base which is replaced by metals and basic radicals to
form salts. Like all other gases, it is condensed by great cold and
pressure to a liquid which freezes and solidifies by its own
evaporation. It is absorbed in large quantities by certain metals
(esp. palladium), forming alloy-like compounds; hence, in view of
quasi-metallic nature, it is sometimes called hydrogenium. It is the
typical reducing agent, as opposed to oxidizers, as oxygen, chlorine,
etc. Bicarbureted hydrogen, an old name for ethylene.
– Carbureted hydrogen gas. See under Carbureted.
– Hydrogen dioxide, a thick, colorless liquid, H2O2, resembling
water, but having a bitter, sour taste, produced by the action of
acids on barium peroxide. It decomposes into water and oxygen, and is
manufactured in large quantities for an oxidizing and bleaching
agent. Called also oxygenated water.
– Hydrogen oxide, a chemical name for water, H -- Hydrogen
sulphide, a colorless inflammable gas, H2S, having the characteristic
odor of bad eggs, and found in many mineral springs. It is produced
by the action of acids on metallic sulphides, and is an important
chemical reagent. Called also sulphureted hydrogen.
Source: Webster’s Unabridged Dictionary 1913 Edition