ion
oxford
views updated May 17 2018ion Atom or group of atoms with an electric (positive or negative) charge resulting from the loss or gain of one or more
electrons. Positive ions are called
cations and move towards the
cathode in
electrolysis; negative ions are called
anions and move towards the
anode.
Ion exchange is when a compound's ions are replaced by ions from another compound with the same charge, and this process is used to remove the
hardness of water. The region of ions in the atmosphere is the
ionosphere. See also
ionic bond;
ionic compound World Encyclopedia
Ion
gale
views updated Jun 08 2018Ion
Forms of ordinary chemical elements that have gained or lost electrons from their orbit around the atomic nucleus and, thus, have become electrically charged. Positive ions (those that have lost electrons) are called cations because when charged electrodes are placed in a solution containing ions the positive ions migrate to the cathode (negative electrode). Negative ions (those that have gained extra electrons) are called anions because they migrate toward the anode (positive electrode). Environmentally important cations include the hydrogen ion (H+) and dissolved metals. Important anions include the hydroxyl ion (OH-) as well as many of the dissolved ions of nonmetallic elements.
See also Ion exchange; Ionizing radiation
Environmental Encyclopedia
ion
oxford
views updated May 21 2018i·on / ˈīən; ˈīˌän/ •
n. an atom or molecule with a net electric charge due to the loss or gain of one or more electrons. See also cation, anion.
The Oxford Pocket Dictionary of Current English
ion
oxford
views updated Jun 11 2018ion (I-ŏn) n. an atom or group of atoms that has lost one or more electrons, making it electrically charged and therefore more chemically active. See
anion,
cation,
electrolyte.
A Dictionary of Nursing
ion
oxford
views updated May 18 2018ion An atom that has acquired an electric charge by the loss (
cation; positive charge) or gain (
anion; negative charge) of one or more electrons.
A Dictionary of Ecology MICHAEL ALLABY
ion
oxford
views updated May 21 2018ion An atom that has acquired an electric charge by the loss (
cation; positive charge) or gain (
anion; negative charge) of one or more electrons.
A Dictionary of Plant Sciences MICHAEL ALLABY
ion
oxford
views updated May 23 2018ion An atom or molecule that has lost or gained one or more electrons, and thus has an electric charge. Positively charged ions are known as cations, because they migrate towards the cathode (negative pole) in solution, while negatively charged ions migrate towards the positive pole (anode) and hence are known as anions.
A Dictionary of Food and Nutrition DAVID A. BENDER
ion
oxford
views updated Jun 08 2018ion An atom or group of atoms that has either lost one or more electrons, making it positively charged (a cation), or gained one or more electrons, making it negatively charged (an anion).
A Dictionary of Biology
ion
oxford
views updated May 08 2018ion Atom that has acquired an electric charge by the loss (cation; positive charge) or gain (anion; negative charge) of one or more electrons.
A Dictionary of Earth Sciences AILSA ALLABY and MICHAEL ALLABY
ion
oxford
views updated May 23 2018ion XIX. — Gr.
ión, prp. n. of
iénai go.
Hence
ionize XIX.
The Concise Oxford Dictionary of English Etymology T. F. HOAD