Chemistry, asked by abhijeetSingh11, 1 year ago

Elaborate the experiment done for the discovery of proton

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Answered by MukunthanSA
0
A proton is a subatomic particle, symbol p or p+, with a positive electric charge of +1e elementary charge and mass slightly less than that of a neutron. Protons and neutrons, each with masses of approximately one atomic mass unit, are collectively referred to as "nucleons".

Proton

The quark content of a proton. The color assignment of individual quarks is arbitrary, but all three colors must be present. Forces between quarks are mediated by gluons.

ClassificationBaryonComposition2 up quarks, 1 down quarkStatisticsFermionicInteractionsGravity, electromagnetic, weak, strong
Symbol p, p+, N+
AntiparticleAntiprotonTheorizedWilliam Prout (1815)DiscoveredEugen Goldstein (1886) and Ernest Rutherford (1917–1919, named by him, 1920)Mass

1.672621898(21)×10−27 kg[1]
938.2720813(58) MeV/c2[2]

1.007276466879(91) u[2]Mean lifetime> 2.1×1029 years (stable)Electric charge+1 e
1.6021766208(98)×10−19 C[2]Charge radius0.8751(61) fm[2]Electric dipole moment< 5.4×10−24 e⋅cmElectric polarizability1.20(6)×10−3 fm3Magnetic moment

1.4106067873(97)×10−26 J⋅T−1[2]
1.5210322053(46)×10−3 μB[2]

2.7928473508(85) μN[2]Magnetic polarizability1.9(5)×10−4 fm3Spin1/2Isospin1/2Parity+1CondensedI(JP) = 1/2(1/2+)

One or more protons are present in the nucleus of every atom; they are a necessary part of the nucleus. The number of protons in the nucleus is the defining property of an element, and is referred to as the atomic number(represented by the symbol Z). Since each element has a unique number of protons, each element has its own unique atomic number.

The word proton is Greek for "first", and this name was given to the hydrogen nucleus by Ernest Rutherford in 1920. In previous years, Rutherford had discovered that the hydrogen nucleus (known to be the lightest nucleus) could be extracted from the nuclei of nitrogen by atomic collisions. Protons were therefore a candidate to be a fundamental particle, and hence a building block of nitrogen and all other heavier atomic nuclei.

In the modern Standard Model of particle physics, protons are hadrons, and like neutrons, the other nucleon (particles present in atomic nuclei), are composed of three quarks. Although protons were originally considered fundamental or elementary particles, they are now known to be composed of three valence quarks: two up quarks and one down quark. The rest massesof quarks contribute only about 1% of a proton's mass, however.[3] The remainder of a proton's mass is due to quantum chromodynamics binding energy, which includes the kinetic energy of the quarks and the energy of the gluon fields that bind the quarks together. Because protons are not fundamental particles, they possess a physical size, though not a definite one; the root mean square charge radius of a proton is about 0.84–0.87 fmor 0.84×10−15 to 0.87×10−15 m.[4][5]

At sufficiently low temperatures, free protons will bind to electrons. However, the character of such bound protons does not change, and they remain protons. A fast proton moving through matter will slow by interactions with electrons and nuclei, until it is captured by the electron cloud of an atom. The result is a protonated atom, which is a chemical compound of hydrogen. In vacuum, when free electrons are present, a sufficiently slow proton may pick up a single free electron, becoming a neutral hydrogen atom, which is chemically a free radical. Such "free hydrogen atoms" tend to react chemically with many other types of atoms at sufficiently low energies. When free hydrogen atoms react with each other, they form neutral hydrogen molecules (H2), which are the most common molecular component of molecular clouds in interstellar space.







Answered by Anonymous
2

E.Goldstein modified the discharge tube experiment by perforated (with small holes) cathode. After evacuating the tube and on applying high voltage, he found that some rays were emitting behind the cathode and moving in the opposite direction of cathode rays. These rays deflect to the negative plate of electric field. So they carry positive charge and were called anode rays or canal rays.

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