Structure of the Atom — Science STD 9 — Question

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 cannal 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 Thompson was a particle.

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