Question

For the ground state, the electron in the $H-atom$ has an angular momentum$=ħ$, according to the simple Bohr model. Angular momentum is a vector and hence there will be infinitely many orbits with the vector pointing in all possible directions. In actuality, this is not true,

• A. D because electrons go around only in horizontal orbits.
• B. because Bohr model gives incorrect values of angular momentum.
  
  
• C. because only one of these would have a minimum energy.
  
• D. angular momentum must be in the direction of spin of electron.
  

Answer 1

The correct option is B because Bohr model gives incorrect values of angular momentum.



According to Bohr model, angular momentum $(L=r_n)$ of revolving electron must be integral multiple of $\frac{h}{2\pi }$ (where $h$ is plank constant)

i.e., $mv{r}_n=\frac{nh}{2\pi }$,

this actually only gives the magnitude of angular momentum and direction can’t be concluded. Hence, it does not give the correct value of angular momentum of revolving electron. That’s why it is wrong to say that $H-atom$ has an angular momentum$=ħ$.

$\text{Final Answer}:$ (a)