Question

Given below are two statements :

Statement I : Bohr’s theory accounts for the stability and line spectrum of Li+ ion.

Statement II : Bohr’s theory was unable to explain the splitting of spectral lines in the presence of a magnetic field.

In the light of the above statement, choose the most appropriate answer from the options
given below:

A. Statement I is true but statement II is false.
B. Both statement I and statement II are true
C. Both statement I and statement II are false
D. Statement I is false but statement II is true

Answer 1

Bohr's theory does not account for the stability and line spectrum of Li+ ion (making statement I false), but Bohr's theory was indeed unable to explain the splitting of spectral lines in the presence of a magnetic field (making statement II true). So, the correct option is D. Statement I is false but statement II is true.

Step-by-step explanation:

In assessing the statements given, it is vital to understand the Bohr model's scope and its limitations. Statement I claims that Bohr’s theory accounts for the stability and line spectrum of the Li+ ion. Bohr's model was a success for the hydrogen atom because it explained the line spectrum with its quantization of angular momentum and energy levels. However, Bohr's model encounters difficulties with atoms or ions that have more than one electron, like Li+, due to electron-electron interactions not accounted for in the model. Therefore, Statement I is false.

Statement II asserts that Bohr’s theory was unable to explain the splitting of spectral lines in the presence of a magnetic field. This phenomenon, known as the Zeeman effect, indeed was not explained by the Bohr model, which was based on quantized orbits without considering external magnetic fields. Therefore, Statement II is true. With the considerations above, the most appropriate answer is: Option D: Statement I is false but statement II is true.