ionization energy

also called  ionization potential,  
 in chemistry, the amount of energy required to remove an electron from an isolated atom or molecule. There is an ionization energy for each successive electron removed; the ionization energy associated with removal of the first (most loosely held) electron, however, is most commonly used.

      The ionization energy of a chemical element, expressed in joules (or electron volts), is usually measured in an electric discharge tube in which a fast-moving electron generated by an electric current collides with a gaseous atom of the element, causing it to eject one of its electrons. For a hydrogen atom, composed of an orbiting electron bound to a nucleus of one proton, an ionization energy of 2.8 × 10−18 joules (13.6 electron volts) is required to force the electron from its lowest energy level entirely out of the atom. The magnitude of the ionization energy of an element is dependent on the combined effects of the electric charge of the nucleus, the size of the atom, and its electronic configuration. Among the chemical elements of any period, removal of an electron is hardest for the noble gases and easiest for the alkali metals. The ionization energy required for removal of electrons increases progressively as the atom loses electrons, because the positive charge on the nucleus of the atom does not change, and therefore, with each removal of an electron, the remainder are held more firmly. The ionization energy is often reported as the amount of energy (in joules) required to ionize the number of atoms or molecules present in one mole (i.e., the amount in grams of a given substance numerically equal to its atomic or molecular weight). One mole of hydrogen atoms has an atomic weight of 1.00 gram, and the ionization energy is 1,312 kilojoules per mole of hydrogen.

      The ionization energy is a measure of the capability of an element to enter into chemical reactions requiring ion formation or donation of electrons. It is also generally related to the nature of the chemical bonding in the compounds formed by the elements. See also binding energy; electron affinity.

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Universalium. 2010.

Look at other dictionaries:

  • ionization energy — jonizacijos energija statusas T sritis Standartizacija ir metrologija apibrėžtis Energijos kiekis, kurį reikia suteikti elektronui, kad jis išlėktų iš sužadinto atomo (molekulės) arba kietajame kūne iš kristalo valentinės juostos peršoktų į… …   Penkiakalbis aiškinamasis metrologijos terminų žodynas

  • ionization energy — jonizacijos energija statusas T sritis fizika atitikmenys: angl. ionization energy; ionizing energy vok. Ionisationsenergie, f; Ionisierungsenergie, f rus. энергия ионизации, f pranc. énergie d’ionisation, f …   Fizikos terminų žodynas

  • ionization energy — jonizacijos energija statusas T sritis chemija apibrėžtis Mažiausia energija, reikalinga elektronui perkelti iš dalelės į begalybę. atitikmenys: angl. ionization energy rus. энергия ионизации …   Chemijos terminų aiškinamasis žodynas

  • ionization energy — noun The energy needed to remove an electron from an atom or molecule to infinity Syn: ionization potential …   Wiktionary

  • ionization energy — amount of energy required to free an electron from an atom …   English contemporary dictionary

  • acceptor ionization energy — akceptoriaus jonizacijos energija statusas T sritis Standartizacija ir metrologija apibrėžtis Energija, kurios reikia akceptoriui jonizuoti. atitikmenys: angl. acceptor ionization energy; acceptor ionizing energy vok. Akzeptor Ionisierungsenergie …   Penkiakalbis aiškinamasis metrologijos terminų žodynas

  • donor ionization energy — donoro jonizacijos energija statusas T sritis Standartizacija ir metrologija apibrėžtis Energija, kurios reikia donorui jonizuoti. atitikmenys: angl. donor ionization energy; donor ionizing energy vok. Donator Ionisierungsenergie, f rus. энергия… …   Penkiakalbis aiškinamasis metrologijos terminų žodynas

  • acceptor ionization energy — akceptoriaus jonizacijos energija statusas T sritis fizika atitikmenys: angl. acceptor ionization energy; acceptor ionizing energy vok. Akzeptor Ionisierungsenergie, f rus. энергия ионизации акцептора, f pranc. énergie d’ionisation d’accepteur, f …   Fizikos terminų žodynas

  • donor ionization energy — donoro jonizacijos energija statusas T sritis fizika atitikmenys: angl. donor ionization energy; donor ionizing energy vok. Donator Ionisierungsenergie, f rus. энергия ионизации донора, f pranc. énergie d’ionisation de donneurs, f …   Fizikos terminų žodynas

  • Ionization potential — The ionization potential, ionization energy or EI of an atom or molecule is the energy required to remove an electron from the isolated atom or ion. More generally, the nth ionization energy is the energy required to strip it of the n th electron …   Wikipedia

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