Question

Which of the following did the planetary model of the atom fail to explain?

		why electrons in atoms don’t radiate all their energy away rapidly
		why alpha particles in Rutherford’s experiment deflected at high angles when incident on atomic foils
		why most alpha particles in Rutherford’s experiment passed with little deflection through atomic foils
		the relationship between orbital radius and energy

Answer 1

Ans. Why electrons in atoms don't radiate all their energy away rapidly.

The flaw to his Rutherford Atomic Model was the fact that electrons orbit the nucleus in a circular fashion. If this was in fact true, then as electrons accelerate around the nucleus, the acceleration would cause the electron to radiate energy in the form of electromagnetic waves (in accordance with Maxwell's theory on electromagnetism), which would imply that the electron would continually lose energy as per the conservation of energy law. Therefore, as the electron orbits, it continually loses kinetic energy and its velocity would decrease, causing it to spiral and eventually smash into the nucleus. This would imply that atoms are naturally unstable. Since atoms are generally stable, this means that the model does not correctly describe the structure of the atom.