atomic number

[ uh-tom ik nuhm ber ]

/ əˈtɒm ɪk ˈnʌm bər /

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Definition of atomic number

noun

the number of positive charges or protons in the nucleus of an atom of a given element, and therefore also the number of electrons normally surrounding the nucleus. Abbreviation: at. no.; Symbol: Z

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Also called pro·ton num·ber [proh ton nuhm ber] /ˈproʊ tɒn ˈnʌm bər/ .

Origin of atomic number

First recorded in 1815–25

Words nearby atomic number

atomic heat, atomic hydrogen, atomicity, atomic mass, atomic mass unit, atomic number, atomic pile, atomic power, atomics, atomic spectrum, atomic structure

Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2022

How to use atomic number in a sentence

There are “light” and “heavy” rare earths, based on their atomic number, and global demand for these metals is climbing.
Lynas is shaking up the supply chain for rare-earth metals|Mary Hui|March 6, 2021|Quartz
“Our members continue to face a number of challenges,” she said.
The Republican War on Kale|Patricia Murphy|January 7, 2015|DAILY BEAST
The number of dissenters though is unprecedented in the modern era.
Democrats Accidentally Save Boehner From Republican Coup|Ben Jacobs, Jackie Kucinich|January 6, 2015|DAILY BEAST
Starting under Theodore Roosevelt and Howard Taft, embassies headed by career diplomats increased in number.
U.S. Embassies Have Always Been for Sale|William O’Connor|January 2, 2015|DAILY BEAST

The number of diplomats was pitiful (45 appointees in 1860), as was the amount of money allocated to them.
U.S. Embassies Have Always Been for Sale|William O’Connor|January 2, 2015|DAILY BEAST
Jett sees this number as a marker of how much the president allows professionals to do the job.
U.S. Embassies Have Always Been for Sale|William O’Connor|January 2, 2015|DAILY BEAST
The country is well inhabited, for it contains fifty-one cities, near a hundred walled towns, and a great number of villages.
Gulliver's Travels|Jonathan Swift
We had six field-pieces, but we only took four, harnessed wit twice the usual number of horses.
Blackwood's Edinburgh Magazine, No. CCCXXXIX. January, 1844. Vol. LV.|Various
There are a number of bacilli, called acid-fast bacilli, which stain in the same way as the tubercle bacillus.
A Manual of Clinical Diagnosis|James Campbell Todd
Five of the number had studied with Liszt before, and the young men are artists already before the public.
Music-Study in Germany|Amy Fay
I do not think the average number of passengers on a corresponding route in our country could be so few as twenty.
Glances at Europe|Horace Greeley

British Dictionary definitions for atomic number

atomic number

noun

the number of protons in the nucleus of an atom of an elementAbbreviation: at. no. Symbol: Z Also called: proton number

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

Medical definitions for atomic number

atomic number

The number of protons in an atomic nucleus; it indicates the position of an element in the periodic table.

Scientific definitions for atomic number

atomic number

The number of protons in the nucleus of an atom. In electrically neutral atoms, this number is also equal to the number of electrons orbiting about the atom's nucleus. The atomic number of an element determines its position in the Periodic Table, and is usually denoted by the letter Z and written as a subscript before an element's symbol, as in 92U.

Cultural definitions for atomic number

atomic number

The number of protons or electrons normally found in an atom of a given chemical element. The higher the atomic number, the heavier the atom is. In a neutral atom, the number of protons and electrons is the same. (See atomic weight and periodic table of the elements.)

atomic number

Definition of atomic number

COMPARE MEANINGS

Origin of atomic number

Words nearby atomic number

Words related to atomic number

How to use atomic number in a sentence

British Dictionary definitions for atomic number

Medical definitions for atomic number

Scientific definitions for atomic number

Cultural definitions for atomic number