Search results
Results From The WOW.Com Content Network
The current theoretical model of the atom involves a dense nucleus surrounded by a probabilistic "cloud" of electrons. Atomic theory is the scientific theory that matter is composed of particles called atoms. The definition of the word "atom" has changed over the years in response to scientific discoveries.
Nicholson is noted as the first to create an atomic model that quantized angular momentum as h/2π. [2] [3] Nicholson was also the first to create a nuclear and quantum theory that explains spectral line radiation as electrons descend toward the nucleus, identifying hitherto unknown solar and nebular spectral lines.
Nicholson's atomic spectra identified many unattributed lines in solar and nebular spectra. [25] [28] [29] [24]: 278 In 1913, Bohr explained the spectral lines of the hydrogen atom, again by using quantization, in his paper of July 1913 On the Constitution of Atoms and Molecules in which he discussed and cited the Nicholson model.
When Bohr began his work on a new atomic theory in the summer of 1912 [8]: 237 the atomic model proposed by J J Thomson, now known as the Plum pudding model, was the best available. [9]: 37 Thomson proposed a model with electrons rotating in coplanar rings within an atomic-sized, positively-charged, spherical volume. Thomson showed that this ...
Ștefan Procopiu performs experiments in which he determines the correct value of electron's magnetic dipole moment, μ B = 9.27 × 10 −21 erg·Oe −1 (in 1913 he is also able to calculate a theoretical value of the Bohr magneton based on Planck's quantum theory). John William Nicholson is noted as the first to create an atomic model that ...
John Dalton's union of atoms combined in ratios (1808) Similar to these views, in 1803 John Dalton took the atomic weight of hydrogen, the lightest element, as unity, and determined, for example, that the ratio for nitrous anhydride was 2 to 3 which gives the formula N 2 O 3. Dalton incorrectly imagined that atoms "hooked" together to form ...
Get AOL Mail for FREE! Manage your email like never before with travel, photo & document views. Personalize your inbox with themes & tabs. You've Got Mail!
In 1804, Dalton explained his atomic theory to his friend and fellow chemist Thomas Thomson, who published an explanation of Dalton's theory in his book A System of Chemistry in 1807. According to Thomson, Dalton's idea first occurred to him when experimenting with "olefiant gas" ( ethylene ) and "carburetted hydrogen gas" ( methane ).