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

According to modern atomic theory atoms of the same element may not be alike in all respect.
e.g. isotopes of chlorine ³⁵₁₇ Cl and ³⁷₁₇ Cl have different atomic masses 35 and 37. This proves Dalton’s Atomic Theory wrong.