Question

WHICH OF THE POSTULATE OF DALTONS ATOMIC THEORY IS CHALLENGED BY THE NEXT GENERATION SCIENTIST ?

Answer 1

Dalton's atomic Theory:

1) All forms of matter are made up of very small particles called atoms.
2) Atoms cannot be created, divided or destroyed as a result of a chemical change.
3) All atoms of an element are identical, and different from those of other elements.
4) Atoms of elements combine in the ratio of whole numbers to produce a large number of compound-atoms of a new substance.
5)The compound-atoms of a particular substance are identical in all properties, and differ from those of other substances.

Following are the drawbacks of Dalton's atomic theory which were challlenged by the Scientist:
1) With the discovery of sub-atomic particles, e.g., electrons, neutrons and protons, the atom can no longer be considered indivisible.
2) All atoms of the same element are not perfectly identical, at least, they differ in their masses. Such elements are called isotopes.
3)Dalton’s atomic theory could not explain why certain substances, containing atoms of the same element, should differ in their properties. For eg. charcoal, graphite and diamond all are made up of only C-atoms, but still their properties are different.
4)Dalton's atomic theory said that atoms of different element have different mass, However two different element can have same mass.