atomic number
noun
: an experimentally determined number characteristic of a chemical element that represents the number of protons in the nucleus which in a neutral atom equals the number of electrons outside the nucleus and that determines the place of the element in the periodic table see Chemical Elements Table
Examples of atomic number in a Sentence
Recent Examples on the Web
The periodic table arranges elements based on their atomic number, or the number of protons each element has in its nucleus.
—
Michael Irving, New Atlas, 25 July 2024
The elements heavier than iron (atomic number 26) form in nature through a process called rapid neutron capture, which often occurs in cataclysmic events such as a collision of two neutron stars.
—Stephanie Pappas, Scientific American, 14 May 2024
With an atomic number of 79 in the periodic table, gold has been a measure of wealth and a store of value for thousands of years.
—Zain Jaffer, Rolling Stone, 26 June 2024
The elements here, starting at atomic number 104 (rutherfordium), have never been found in nature.
—Stephanie Pappas, Scientific American, 14 May 2024
See all Example Sentences for atomic number 
Michael Irving, New Atlas, 25 July 2024
The elements heavier than iron (atomic number 26) form in nature through a process called rapid neutron capture, which often occurs in cataclysmic events such as a collision of two neutron stars.
—Stephanie Pappas, Scientific American, 14 May 2024
With an atomic number of 79 in the periodic table, gold has been a measure of wealth and a store of value for thousands of years.
—Zain Jaffer, Rolling Stone, 26 June 2024
The elements here, starting at atomic number 104 (rutherfordium), have never been found in nature.
—Stephanie Pappas, Scientific American, 14 May 2024
See all Example Sentences for atomic number
These examples are programmatically compiled from various online sources to illustrate current usage of the word 'atomic number.' Any opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback about these examples.
Articles Related to atomic number
Dictionary Entries Near atomic number
Cite this Entry
“Atomic number.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/atomic%20number. Accessed 15 Sep. 2024.
Copy CitationMedical Definition
atomic number
noun
atomic num·ber
-ˈnəm-bər 
: an experimentally determined number characteristic of a chemical element that represents the number of protons in the nucleus which in a neutral atom equals the number of electrons outside the nucleus and that determines the place of the element in the periodic table see Chemical Elements Table
Love words? Need even more definitions?
Merriam-Webster unabridged
Share