why is Dalton atomic theory discarded?

Dear Student ,

Please find below the solution to the asked query:

Dalton's Atomic Theory was discarded because of following reasons : 

1) According to Dalton's theory atoms are indivisible. However, the atom is further subdivided into protons, neutrons and electrons.

2) The atoms of same elements are not similar in all respect. They may vary in mass and density. These are known as isotopes. For example: chlorine has two isotopes having mass numbers 35 a.m.u and 37 a.m.u.

3) Atoms of different elements are not different in all respects. Atoms of different elements that have the same atomic mass are called isobar.

4) According to Dalton atoms of different elements combine in simple whole number ratio to form compounds. This is not seen in complex organic compounds like sugar C₁₂H₂₂O₁₁.

5)The theory fails to explain the existence of allotropes.
 

Hope this information will clear your doubts about this topic. 

If you have any more doubts just ask here on the forum and our experts will try to help you out as soon as possible.

Regards
Akanksha