alpha particle
a positively charged particle consisting of two protons and two neutrons, emitted in radioactive decay or nuclear fission; the nucleus of a helium atom.
Origin of alpha particle
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Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2024
How to use alpha particle in a sentence
Some particles — including protons, neutrons, alpha particles and beta particles — travel through space at high speeds.
Mercury 203 plus an alpha particle gives nice, stable Lead 207.
The Bramble Bush | Gordon Randall GarrettAn alpha particle is the nucleus of a helium atom and is made up of two protons and two neutrons; it carries two positive charges.
LRL Accelerators | Lawrence Radiation LaboratoryThere can thus be no doubt that the alpha particle becomes a helium atom when its positive charge is neutralized.
A Brief Account of Radio-activity | Francis Preston VenableThis stopping power of an atom for an alpha particle is approximately proportional to the square root of its atomic weight.
A Brief Account of Radio-activity | Francis Preston Venable
Ionium expels an alpha particle and becomes radium, which is a bivalent element resembling barium belonging to the second group.
A Brief Account of Radio-activity | Francis Preston Venable
British Dictionary definitions for alpha particle
a helium-4 nucleus, containing two neutrons and two protons, emitted during some radioactive transformations
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012
Scientific definitions for alpha particle
A positively charged particle that consists of two protons and two neutrons bound together. It is emitted by an atomic nucleus undergoing radioactive decay and is identical to the nucleus of a helium atom. Because of their relatively large mass, alpha particles are the slowest and least penetrating forms of nuclear radiation. They can be stopped by a piece of paper. See more at radioactive decay.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
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