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mass number
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noun Physics.
the integer nearest in value to the atomic weight of an atom and equal to the number of nucleons in the nucleus of the atom. Symbol: A
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Origin of mass number
First recorded in 1920ā25
Words nearby mass number
Dictionary.com Unabridged
Based on the Random House Unabridged Dictionary, Ā© Random House, Inc. 2022
How to use mass number in a sentence
British Dictionary definitions for mass number
mass number
noun
the total number of neutrons and protons in the nucleus of a particular atomSymbol: A Also called: nucleon number
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition
Ā© William Collins Sons & Co. Ltd. 1979, 1986 Ā© HarperCollins
Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012
Scientific definitions for mass number
mass number
The total number of protons and neutrons in the nucleus of an atom. For example, nitrogen has 7 protons and 7 neutrons in its nucleus, giving it a mass number of 14. Isotopes of elements are distinguished by their mass number; for example, carbon-12 and carbon-14 have mass numbers of 12 and 14 respectively. Also called nucleon number Compare atomic mass atomic weight.
The American HeritageĀ® Science Dictionary
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