A nonmetallic element that is the simplest and lightest of the elements, is normally a colorless odorless highly flammable diatomic gas, and is used especially in synthesis.
Hydrogen is a chemical element with chemical symbol H and atomic number 1. With an atomic weight of 7000100794000000000♠1.00794 u, hydrogen is the lightest element on the periodic table. Its monatomic form (H) is the most abundant chemical substance in the universe, constituting roughly 75% of all baryonic mass. Non-remnant stars are mainly composed of hydrogen in its plasma state. The most common isotope of hydrogen, termed protium (name rarely used, symbol 1 H), has one proton and no neutrons. Noun. 1. hydrogen bond-a chemical bond consisting of a hydrogen atom between two electronegative atoms (e.g., oxygen or nitrogen) with one side be a covalent bond and the other being an ionic bond. bond, chemical bond-an electrical force linking atoms. hydrogen bond. n. 1. (Chemistry) a weak chemical bond between an electronegative atom, such as fluorine, oxygen, or nitrogen, and a hydrogen atom bound to another electronegative atom. LINK / CITE ADD TO WORD LIST. noun. The element hydrogen on the periodic table. The element hydrogen on the periodic table. The definition of hydrogen is a gaseous element that has no color or odor and is flammable. 1 An atom of hydrogen is the smallest of all elements that exist. 2  Hydrogen is the most plentiful element in the universe. 3  An atom of hydrogen is made up of two subatomic particles, one electron and one proton. 4  Hydrogen exists in three forms-hydrogen, deuterium, and tritium Full Definition of HYDROGEN. : a nonmetallic element that is the simplest and lightest of the elements, is normally a colorless odorless highly flammable diatomic gas, and is used especially in synthesis — see element table — compare deuterium, tritium. — hy·drog·e·nous \hī-ˈdrae-ˈdrä-jə\ nəs. adjective Word History of HYDROGEN. When hydrogen is burned it combines with oxygen to make water. That fact accounts for the name of this gas. The word hydrogen was formed from two Greek roots. The first, hydro- , means “ water, ” and the second, -gen, means “ giving rise to, producing. Hydrogen is the simplest element. An atom of hydrogen consists of only one proton and one electron. It's also the most plentiful element in the universe. Despite its simplicity and abundance, hydrogen doesn't occur naturally as a gas on the Earth-it's always combined with other elements.  Hydrogen. (Science: chemistry, element) hydrogen is a gas element which has an atomic number of 1 and an atomic weight of 1.0079. It combines with oxygen to form water (H20) and is present in all organic compounds. a few types of bacteria can metabolise atmospheric hydrogen (H2).  Medical Definition of HYDROGEN BOND. : an electrostatic attraction between a hydrogen atom in one polar molecule (as of water) and a small electronegative atom (as of oxygen, nitrogen, or fluorine) in usually another molecule of the same or a different polar substance. — hydrogen bonding noun. ADVERTISEMENT hydrogen bond. A chemical bond in which a hydrogen atom that is already bonded to an atom in a molecule forms a second bond with another atom, either in the same molecule or in a different one. The second atom is usually of a type that strongly attracts electrons, such as nitrogen or oxygen. hydrogen bond. n. 1. (Chemistry) a weak chemical bond between an electronegative atom, such as fluorine, oxygen, or nitrogen, and a hydrogen atom bound to another electronegative atom.
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define hydrogen