Question

According to Dalton's Atomic Theory, atoms of the same element are identical in all respects. But according to the Modern Atomic theory, this postulate is proved wrong.Explain.​

Answer 1

Answer :-

According to the Modern Atomic theory , Dalton's Atomic theory is wrong which says that --> Atoms of same element are identical in all respects .

Reason:-

In modern Atomic theory it is found that Atoms of same element can have different Atomic size , Atomic mass , No. of protons , etc.

The discovery of Isotopes of elements is the main reason for discarding the Dalton's Postulate, to prove it let us consider the Isotopes of Hydrogen .

Hydrogen have three Isotopes .

1. $H^{1}_1$
2. $H^{2}_1$
3. $H^{3}_1$

Their names :-

1. Protium

2. Deuterium

3. Tritium

So we can clearly see that they are the Atoms of same element but have different mass no.

Hence , that's why the Dalton's Postulate was discarded by the Modern Atomic Theory

Hope it helps you