Discovery Of Electron, Proton, And Neutron-Discovery Of Proton

Definition of Protons:

A subatomic particle that is similar to the nucleus of a hydrogen atom, that, like the neutron, is a subset of all other nuclei of an atom, that carries a net charge numerically equal to the charge of an electron, and that has a mass of 1.673×10-27 kilograms

History

• Protons were discovered for the first time in the year 1815.
• An English chemist William Sprout suggested a concept of atoms that made the assumption that all atoms were composed of hydrogen atoms.
• These hydrogen atoms were referred to by him as protyles.
• After this, a more concrete assumption regarding the discovery of protons was made by a German physicist by the name of Eugene Goldstein
• This was when he discovered canal rays in the year 1886
• After this, on further examination, it was found that in the case of hydrogen the charge to mass ratio of the hydrogen ion was the highest among other gases.
• It was also incurred that the hydrogen ion had the smallest size among other ionised gases.
• Later the nucleus of the atom was discovered by the scientist Ernest Rutherford in the year 1911 with the help of his famous experiment with gold foil.
• This experiment led to the conclusion that all the positively charged particles in a nucleus were concentrated in the centre and the rest of the space of the atom was empty.
• He also concluded that the total number of positively charged particles in an atom was equal to the total number of negatively charged particles in it.

Discovery of protons

• The discovery of the protons is credited to the gold foil experiment carried out by the famous scientist Ernest Rutherford.
• Rutherford is also recognized for proving that the hydrogen atom was the building block for the nuclei of all atoms.
• The conclusions from his gold foil experiment also form the basis for the discovery of the nucleus.
• Earnest Rutherford inferred that hydrogen nuclei were detected by the scintillation detectors when a beam of alpha particles was shot into the air.
• He also discovered that the hydrogen nuclei were produced through the atoms of nitrogen that were present in the atmosphere.
• Apart from that, Rutherford also proceeded to fire beams of alpha particles into the pure nitrogen gas and observed that a large number of hydrogen nuclei were produced.
• This led him to conclude that the hydrogen nucleus had emerged from the nitrogen atoms, proving the theory that the hydrogen nucleus formed the core of all other atoms.

This experiment was also significant as it led to the first nuclear reaction.

This reaction was represented as the equation: –

14N + α → 17O + p.

In this equation

 α= the alpha particle which contains two protons and two neutrons.

p = proton

In the times to come, this hydrogen nucleus was named as the proton, one of the major parts of the nucleus of the atom.

Characteristics of a Proton

It has now been established that the proton along with the electron and neutron is one of the most important subatomic particles in an atom.

The characteristics of a proton are different from the neutron and electron and can be stated as below: –

• The charge of a proton is positive.
• The location of the protons is inside the nucleus.
• The rest mass of a proton is 1.67262 × 10−27 kg(~ 1 a.m.u. which is equal to1.836 times the mass of an electron.
• The charge on 1 proton is 1.6 x 10-19 C.
• The value of one coulomb is equal to the charge on 6.241 x 1018 protons. 

Conclusion

The major part of an atom’s mass and the whole of its positive charge lies in the small core of the atom called the nucleus. This positively charged particle is referred to as the Proton.

The larger portion of an atom is mostly an empty space.

The positive charge of a nucleus is counterbalanced by a negative charge as the number of positive particles in an atom is equal to the number of negative particles in the nucleus of the atom. This makes the atom electrically neutral.