proton

[ proh-ton ]

noun

, Physics, Chemistry.

1. a positively charged elementary particle that is a fundamental constituent of all atomic nuclei. It is the lightest and most stable baryon, having a charge equal in magnitude to that of the electron, a spin of ½, and a mass of 1.673 × 10 -27 kg. : P

proton

/ ˈprəʊtɒn /

noun

1. a stable, positively charged elementary particle, found in atomic nuclei in numbers equal to the atomic number of the element. It is a baryon with a charge of 1.602176462 × 10 ^–19coulomb, a rest mass of 1.672 62159 × 10 ^–27kilogram, and spin 1 2

proton

/ prō′tŏn′ /

1. A stable subatomic particle in the baryon family having a mass of 1.672 × 10 ^-24 grams (1,836 times that of the electron) and a positive electric charge of approximately 1.602 × 10 ^-19 coulombs. Protons make up part of the nucleus of all atoms except hydrogen, whose nucleus consists of a single proton. In neutral atoms, the number of protons is the same as the number of electrons. In positively charged atoms, the number of protons is greater than the number of electrons, and in negatively charged atoms electrons outnumber protons. Protons are believed to be composed of two up quarks and one down quark.
2. See Table at subatomic particle

proton

1. An elementary particle with a positive charge , found in the nucleus of an atom .

Notes

Protons and neutrons make up most of an atom's mass .

A proton is over a thousand times heavier than an electron .

Other Words From

• pro·tonic adjective

Word History and Origins

Origin of proton¹

Term first suggested in 1920 by English physicist Ernest Rutherford as noun use of Greek prôton, neuter of prôtos “first,” the proton being the constituent of hydrogen nuclei, and formed on the analogy of electron; first, electron

Word History and Origins

Origin of proton¹

C20: from Greek prōtos first

Example Sentences

Annabel was given a 50% chance of survival when she was diagnosed with the cancer at the age of four and underwent a gruelling treatment regime including surgery, high-dose chemotherapy, proton beam radiotherapy, immunotherapy and a stem cell transplant.

From BBC

The hydrogen atom — one proton, one electron — loves to hook up with other elements.

From Los Angeles Times

It would have also yielded a small fraction of exponentially smaller black holes, with the mass of a rhino and a size much smaller than a single proton.

From Science Daily

Proton therapy has both biological and physical advantages over traditional radiation therapy using photons.

From Science Daily

This allows proton radiation to be delivered specifically to the targeted area, limiting the amount that reaches nearby normal tissues.

From Science Daily