Quantum theory and Bohr atom model

Bohr atom model Rutherford’s model laid the foundation of the model picture of the atom. The Rutherford model, on the other hand, provided no information on the position of the electrons or how they were organized around the nucleus. Rutherford saw that electrons were circling the nucleus. However, according to classical physics, an electron traveling … Read more

Moseley’s law determination of the atomic number

Moseley’s law Moseley’s law is an empirical law relating to atoms’ distinctive x-rays. Henry Moseley, an English physicist, developed and published the law in 1913-1914. Hitherto atomic number was designated as the ‘position number’ of a particular element in the Periodic Table. Moseley found that when cathode rays struck different elements used as anode targets … Read more

Positive rays

Positive rays/anode ray: Eugen Goldstein utilized a cathode discharge tube with a hole in 1886. While cathode rays were flowing away from the cathode, he noticed that colored rays were being created at the same time, passing through the perforated cathode and causing a light on the wall opposite the anode. Thomson investigated these rays … Read more

Measurement of e/m for electrons

Measurement of e/m for electrons: The ratio of charge to mass (e/m) for an electron was measured by J.J. Thomson (1897) using the apparatus shown in the Figure below. On the fluorescent screen, electrons form a brilliant light spot at X. The electrons are initially deflected in a circular route by a magnetic field, while … Read more

Discovery of electron

Discovery of electron

Discovery of electron Discovery of electron: All matter, according to John Dalton (1805), is made up of tiny particles called atoms. He imagined the atom as a single hard solid particle that could not be subdivided. By the end of the nineteenth century, enough scientific data had been collected to indicate that the atom is … Read more