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

Would formic acid useful basis for buffer solution, Formic acid is a weak a...

Formic acid is a weak acid along with a pKa of 3.75. Name of this comes through the Latin term "formica" ("ant") since it is extremely plentiful into the secretions of several spec

Detect the presence of synthetic food colours, Q. Detect the presence of sy...

Q. Detect the presence of synthetic food colours in the given samples? Objectives After conducting this activity, you will be able to: • describe the kind of natural

Radiometric titration, principle and explanation of radiometric titration

principle and explanation of radiometric titration

Physical properties of alkyl halides, Physical properties of alkyl halides ...

Physical properties of alkyl halides (1) Physical state: Methoxy methane and methoxy ethane are gases whereas other members are volatile liquid along with pleasant smell.

Polymers., uses of the polymer bakelite

uses of the polymer bakelite

Electrochemistry, reversible and irreversible cell with example

reversible and irreversible cell with example

Titrations, what is the chemical raction of a titration using sodium hydrox...

what is the chemical raction of a titration using sodium hydroxide and phenophthalein?

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