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. Symbol: Z.

Abbreviation: at. no.;

Also called proton number.

Origin

1815-25

Examples from the web for atomic number

From left to right, the atomic number — the number of protons in the nucleus of an atom — increases.
This produces a "pure atomic" compound with an atomic number.
Tell people the chemical element whose atomic number corresponds to your age.
Atoms with the same atomic number make up a chemical element.
Any of the abundant metallic elements of atomic number 57 through 71.
I'm pretty sure Germanium already exists, atomic number 32.
Lithium's atomic number is three.
The higher atomic number elements are created by supernovas.
The process of creating higher atomic number elements from lower ones is fusion.
All you need is the atomic number and a geometric structure.

British Dictionary definitions for atomic number

atomic number

noun

the number of protons in the nucleus of an atom of an element at. no., Z Also called proton number

atomic number in Medicine

atomic number n.
Abbr. at. no., at no
The number of protons in an atomic nucleus; it indicates the position of an element in the periodic table.

atomic number in Science

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.

atomic number in Culture

atomic number definition

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.)