Discovery of sub-atomic particles , Chemistry

Assignment Help:

DISCOVERY OF SUB-ATOMIC PARTICLES

The atomic theory of the Greek philosophers, Leucippus and Democretus (400 B.C.) held that continued subdivision of matter would ultimately yield atoms which would not be further divided. The word 'atom' is derived from the Greek word, aromos, which means "uncut" or indivisible. Dalton (1808) based his atomic theory on the ideas of Democretus and was able to explain the laws of chemical combination.

Toward the end of nineteenth century, it began to appear that the atom itself might be composed of even smaller particles. This discovery was brought about by experiments with electricity. Attempts to pass a high voltage electric current through gases under reduced pressure led to Julius Plucker's discovery (1859) of cathode rays, Fig. 1.1. The cathode rays stream from the negative electrode, which is called the cathode. These rays consist of negatively charged particles which travel in straight lines. The cathode rays give off flashes of light, when they strike a screen coated with substances like zinc sulphide. The picture tubes in television sets and computer monitors, function on this principle.


Related Discussions:- Discovery of sub-atomic particles

Chemical process analysis, A useful model of interfacial mass transport mak...

A useful model of interfacial mass transport makes three assumptions: (i) there is a difference between the concentrations of A at the interface, C A denoted C A in Phases I

Saturated and unsaturated hydrocarbons, Saturated and unsaturated hydrocarb...

Saturated and unsaturated hydrocarbons The compounds of carbon and hydrogen in which carbon atoms are linked to each other by single covalent bonds(C-C) are known as alkanes. T

Antipyretics, chemistry and mechanism of action

chemistry and mechanism of action

Ionization energy of group, Ionization energy of group: Why does Ioniz...

Ionization energy of group: Why does Ionization energy of group IIA elements decrease from Be to Ra?  A. As the atomic size increases from Be to Ra, the attraction between

Electromeric effect, types of elecromeric effect and applications

types of elecromeric effect and applications

State the term - ferrites, State the term - Ferrites Ferrites are used ...

State the term - Ferrites Ferrites are used as ferromagnetic materials for high frequency applications like TV tubes, memory devices, high-speed switches, microwave application

Hydrogen, hydrogen behave as a metal at low pressure only why

hydrogen behave as a metal at low pressure only why

The formula of its phosphate, Chloride of metal is MCl 2  . The formula of...

Chloride of metal is MCl 2  . The formula of its phosphate will be: (1) M 2 PO 4                                                (2)  M 3 (Po 4 ) 2 (3)  M 2 (

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd