NEETPhysicsAtomic Physics
The radius of the n^ th Bohr orbit of a Be ³⁺ ion is equal to the radius of the first Bohr orbit of a hydrogen atom. What is the value of n ?
Options
- A2
- B1
- C3
- D4
Correct answer
A. 2
Step-by-step solution
The radius of the n^ th Bohr orbit of a hydrogen-like species is given by: r_n = a₀ n^2 Z For a Be ³⁺ ion, the atomic number Z = 4 . Therefore, the radius of its n^ th orbit is: r_n = a₀ n^2 4 The radius of the first Bohr orbit of a hydrogen atom ( Z = 1, n = 1 ) is a₀ . According to the given condition: a₀ n^2 4 = a₀ n^2 4 = 1 n^2 = 4 n = 2 Answer: 2