Question

Explain how the modern atomic theory contradicted Dalton’s atomic theory.

Answer 1

Modern atomic theory contradicted Dalton Atomic Theory as :

1. Atom is no longer indivisible as an atom has been divided and has subatomic particles
   (a) Protons
   (b) Neutrons
   (c) Electrons
2. Atoms of the same element may have different properties
   i.e. Isotopes \[\ce{^1_1H,^2_1H,^3_1H}\]
3. Atoms of different elements may have the same properties i.e. Isobars
4. Atoms combine with other atoms may not be in a simple whole-number ratio i.e. C₁₂H₂₂O₁₁ (Sugar).
5. Atom can be destroyed and converted into energy.