Inorganic Chemistry/The Discoveries of Electrons, Protons and Neutrons

The Discovery of the Electrons

The electron was discovered in 1896, by the British physicist J. J. Thomson, using a cathode rays while doing discharge tube experiments. Thomson also determined e/m, ratio of the charge e to the mass m of the material particle which constituted these rays. Note that the first clues that the electron existed were first noticed by German physicist Johann Wilhelm Hittorf in 1869 when he discovered that the glow emitted from the cathode that increased in size with decrease in gas pressure. Hittorf was studding the electrical conductivity in rarefied gases.

The particle first named "corpuscles" by Thomson, it was later renamed "electron" by a proposal of Irish physicist George F. Fitzgerald that has gained universal acceptance.

Protons are subatomic particles that, with neutrons and electrons, are the principal constituents of atoms.

Protons are positively charged particles that reside in the nucleus of an atom. These protons add the overall positive charge of an atom. The mass of the proton is about 1,840 times the mass of the electron.

Through scientific discovery, protons have been accepted as the particle that contributes to the positive charge of an atom. The discovery of protons can be attributed to Rutherford.

In 1886 Goldstein discovered existence of positively charged rays in the discharge tube by using perforated cathode. These rays were named as anode rays or canal rays.

In 1899, Rutherford discovered alpha and beta ‘rays’ from uranium. He later demonstrated that alpha rays are the nuclei of helium atoms. He discovered in 1914 that the nucleus of an atom constituted and extremely dense but small fraction of the volume of an atom and that this nucleus was positive in charge.

Given the discoveries of electrons in 1897 by Thomson, Rutherford and other scientists decided that a positively charged particle must exist to center the electron to create equally neutral atoms.

Thompson proposed the name ‘positive rays’. Rutherford, in 1914, suggested that this something that was positively charged or the sportive ray of Thompson was a particle.

He gave the name ‘positive electron’ to it. The word ‘proton’ was assigned to this particle by 1920.

Rutherford continued to do research until his death, but the proton was his last big discovery.

Later the name of negatively charged particle (electron) was coined by Johnstone Stoney in 1891.

The Discovery of the Protons

Protons are subatomic particles that, with neutrons and electrons, are the principal constituents of atoms.

Protons are positively charged particles that reside in the nucleus of an atom. These protons add the overall positive charge of a molecule. The mass of the proton is 1.6727g x 10 raised to -24, the electron 9.110g x 10 raised to -28.

Through scientific discovery, protons have been accepted as the particle that contributes to the positive charge of an atom. The discovery of protons can be attributed to Rutherford.

In 1886 Goldstein discovered existence of positively charged rays in the discharge tube by using perforated cathode. These rays were named as anode rays or canal rays.

In 1899, Rutherford discovered alpha and beta ‘rays’ from uranium. He later demonstrated that alpha rays are the nuclei of helium atoms. He discovered in 1914 that the nucleus of an atom constituted and extremely dense but small fraction of the volume of an atom and that this nucleus was positive in charge.

Given the discoveries of electrons in 1897 by Thomson, Rutherford and other scientists decided that a positively charged particle must exist to center the electron to create equally neutral atoms.

Thomson proposed the name ‘positive rays’. Rutherford, in 1914, suggested that this something that was positively charged or the sportive ray of Thomson was a particle.

He gave the name ‘positive electron’ to it. The word ‘proton’ was assigned to this particle by 1920.

Rutherford continued to do research until his death, but the proton was his last big discovery.