electron

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electron

 [e-lek´tron]
any of the negatively charged particles arranged in orbitals around the nucleus of an atom and determining all of the atom's physical and chemical properties except mass and radioactivity. Electrons flowing in a conductor constitute an electric current; when ejected from a radioactive substance, they are beta particles.ƒ

The number of electrons revolving around the nucleus of an atom is equal to its atomic number. An atom of oxygen, for instance, which has an atomic number of 8, has eight electrons in orbit around the nucleus in a manner similar to the planets revolving around the sun in our solar system.

Electrons greatly influence the behavior of an atom toward other atoms. The combination of various elements to form compounds is brought about by the losing or gaining of electrons; the process is sometimes called “sharing” of electrons. For example, the combination of the elements sodium and chlorine produce the compound sodium chloride (table salt). This is accomplished by the transfer of one electron from the outer electron shell of the sodium atom to the outer electron shell of the chlorine atom. This combining of elements by the loss or gain of electrons is called electrovalence.
Miller-Keane Encyclopedia and Dictionary of Medicine, Nursing, and Allied Health, Seventh Edition. © 2003 by Saunders, an imprint of Elsevier, Inc. All rights reserved.

e·lec·tron (β-),

(ē-lek'tron),
One of the negatively charged subatomic particles that orbit the positive nucleus, in one of several energy levels called shells; in mass they are estimated to be 1/1836.15 of a proton; when emitted from inside the nucleus of a radioactive substance, electrons are called β particles. A nucleus and its electrons constitute an atom.
See also: shell.
[electro- + -on]
Farlex Partner Medical Dictionary © Farlex 2012

e·lec·tron

(β-) (ĕ-lek'tron)
One of the negatively charged subatomic particles that are distributed about the positive nucleus and with it constitute the atom; in mass they are estimated to be 1/1836.15 of a proton; when emitted from inside the nucleus of a radioactive substance, electrons are called beta particles.
[electro- + -on]
Medical Dictionary for the Health Professions and Nursing © Farlex 2012

Electron

One of the small particles that make up an atom. An electron has the same mass and amount of charge as a positron, but the electron has a negative charge.
Gale Encyclopedia of Medicine. Copyright 2008 The Gale Group, Inc. All rights reserved.

e·lec·tron

(ĕ-lek'tron)
Negatively charged subatomic particles that orbit the positive nucleus, in one of several energy levels called shells. A nucleus and its electrons constitute an atom.
[electro- + -on]
Medical Dictionary for the Dental Professions © Farlex 2012
References in periodicals archive ?
The modification of chemical structures by introduction of several electron donor groups can greatly modulate and improve the electronic and optical properties of the studied compounds.
P: primary electron donor; BChl: bacteriochlorophyll; BPheo: bacteriopheophytin; [Q.sub.A]: primary quinone type electron acceptor; [Q.sub.B]: secondary quinone type electron acceptor.
The availability of these electron donors, in turn, promoted reductive dechlorination activity.
The larger [E.sup.2] value means that the interaction between electron donors and acceptors is more intensive, that is, more electrons donating tendency from electron donors to acceptors and greater extent of charge-transfer interaction across the whole system.
Consumption of [H.sub.2] by a dehalogenating organism (e.g., Desulfomonile tiedjet) and/or methanogenic populations creates an environment in which benzoate fermentation is feasible and biodegradation of 3-CB can be sustained without the addition of an electron donor (Dolfing and Tiedje 1986).
The incubation mixture consisted of 0.2 [micro]mol fenthion or fenthion sulfoxide, 1 [micro]mol of an electron donor and liver microsomes (2-3 mg protein) or cytosol (1-2 mg protein) in a final volume of 1 mL of 0.1 M K,Na-phosphate buffer (pH 7.4).
An aqueous Ti[O.sub.2] suspension (0.5 g/L, 500 mL) containing chloroplatinic acid as a Pt precursor (100 [micro]M) and methanol as an electron donor (1M) was irradiated with a 200 W mercury lamp for 30 min.
Of the aqueous molecules, the best known is vitamin C (ascorbate), which is the most powerful electron donor and the first plasma antioxidant to be sacrificed upon exposure to oxidative stress (11).
"In these systems,' he says, "[hydrogen gas] is often present in only low levels and [carbon dioxide] is abundant, so that [elemental iron] could serve as a significant electron donor.'
Normally, the active layer of bulk-heterojunction solar cell consists of different conjugated polymer, which acts as an electron donor and blends with an electron acceptor based on fullerene derivatives such as [6,6]-phenyl-[C.sub.61]-butyric acid methyl ester, PCBM.
A heterojunction is built with two types of semiconductors in touch: one is n-type or electron acceptor (A) and another one is p-type or electron donor (D).

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