Given below are two statements: one is labelled as Assertion A and the other is labelled as Reason R .…

Given below are two statements: one is labelled as Assertion A and the other is labelled as
Reason R.
Assertion A: The Bohr model is applicable to hydrogen and hydrogen-like atoms only.
Reason R : The formulation of Bohr model does not include repulsive force between electrons.
In the light of the above statements, choose the correct answer from the options given below :
  1. Both $\mathrm{A}$ and $\mathrm{R}$ are true but $\mathrm{R}$ is NOT the correct explanation of $\mathrm{A}$.
  2. $\mathrm{A}$ is false but $\mathrm{R}$ is true.
  3. Both $\mathrm{A}$ and $\mathrm{R}$ are true and $\mathrm{R}$ is the correct explanation of $\mathrm{A}$.
  4. $\mathrm{A}$ is true but $\mathrm{R}$ is false.

Solution

Both statements are true, and the absence of electron-electron repulsion in Bohr's formulation is exactly why it works only for one-electron systems (hydrogen and hydrogen-like ions). - Assertion A is true: Bohr's model applies only to atoms with a single electron. - Reason R is true: Bohr treated only the Coulomb attraction between nucleus and electron, omitting any repulsive force between multiple electrons. - Since ignoring e-e repulsion prevents extension to multi-electron atoms, R correctly explains A.

Asked in: JEE Main 2025 (03 Apr Shift 2)

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