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

Gases, a small 0.600ml bubble forms at the bottom of a lake where the tempe...

a small 0.600ml bubble forms at the bottom of a lake where the temperature is 4.0 degrees Celsius and the pressure is 2.40 atm. What volume will the bubble occupy near the surface

Dithizone, can -COOH group be attached with the phenyl group of dithizone?

can -COOH group be attached with the phenyl group of dithizone?

Shiff base, i am synthesing the azipines and i wana to fet the azipine with...

i am synthesing the azipines and i wana to fet the azipine with different subsituites. how can i get with triflouro subsituited azipines?

Poisnous gases released during burning of the plastic , What are the major ...

What are the major poisnous gases released during burning of the plastic substances? Ans) It is high time that we start taking concrete steps in order to prevent pollution or else

Determination of molecular mass - victor meyer method , Determination of Mo...

Determination of Molecular Mass - Victor Meyer method Molecular mass of volatile liquids and solids that can be easily ascertained from the application of Avogadro hypothesis a

Balancing equations, what is the balanced equation of the burning of an unk...

what is the balanced equation of the burning of an unknown hydrocarbon, C4H9 in air

Hydrogen peroxide, Hydrogen Peroxide Hydrogen peroxide is the other im...

Hydrogen Peroxide Hydrogen peroxide is the other important hydride of oxygen. The oldest method of its preparation is by the action of dilute sulphuric acid on barium peroxide

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