Atoms · Question 18

Considering Bohr's atomic model for hydrogen atom : Choose the correct answer from the options given below :

1. (A), (B) only
2. (A), (D) only
3. (A), (C) only
4. (B), (D) only

Answer

(1) (A), (B) only

Solution

En = -13.6 Z2n2 eV; compare Z2n2.

H, ground state (Z = 1, n = 1): Z2n2 = 1

(A) He+, first excited (Z = 2, n = 2): 44 = 1 ⇒ correct

(B) Li++, second excited (Z = 3, n = 3): 99 = 1 ⇒ correct

(C) He+, ground (Z = 2, n = 1): 4 1 ⇒ incorrect

(D) He+ (n = 2): 1, but Li++ ground: 9 ⇒ incorrect

(A), (B) only

Answer: (1)