Search results
Results From The WOW.Com Content Network
A proton is a stable subatomic particle, symbol p, H +, or 1 H + with a positive electric charge of +1 e (elementary charge).Its mass is slightly less than the mass of a neutron and approximately 1836 times the mass of an electron (the proton-to-electron mass ratio).
An atom consists of a small, heavy nucleus surrounded by a relatively large, light cloud of electrons. An atomic nucleus consists of 1 or more protons and 0 or more neutrons. Protons and neutrons are, in turn, made of quarks. Each type of atom corresponds to a specific chemical element. To date, 118 elements have been discovered or created.
In particle physics, an elementary particle or fundamental particle is a subatomic particle that is not composed of other particles. [1] The Standard Model presently recognizes seventeen distinct particles—twelve fermions and five bosons .
† ^ Particle has not yet been observed. [a] ^ The masses of the proton and neutron are known with much better precision in daltons (Da) than in MeV/c 2. In atomic mass units, the mass of the proton is 1.007 276 466 5789 (83) Da [28] whereas that of the neutron is 1.008 664 916 06 (40) Da. [29] [b] ^ At least 10 35 years. See proton decay.
The elementary charge, usually denoted by e, is a fundamental physical constant, defined as the electric charge carried by a single proton (+1 e) or, equivalently, the magnitude of the negative electric charge carried by a single electron, which has charge −1 e.
Ordinary nucleons (symbol N, meaning either a proton or neutron), by contrast, have a mass of about 939 MeV/c 2, and both intrinsic spin and isospin of 1 / 2 . The Δ + (uud) and Δ 0 (udd) particles are higher-mass spin-excitations of the proton (N +, uud) and neutron (N 0, udd), respectively. The Δ ++ and Δ −
Particle name Particle symbol Antiparticle symbol Quark content Rest mass ... The estimated mass of the new particles was very rough, about half a proton's mass. More ...
In physics, the proton-to-electron mass ratio (symbol μ or β) is the rest mass of the proton (a baryon found in atoms) divided by that of the electron (a lepton found in atoms), a dimensionless quantity, namely: μ = m p /m e = 1 836.152 673 426 (32). [1]