Question

When hydrogen atom is in its first excited level, its radius is
(a) four times its ground state radius
(b) twice
(c) same
(d) half

Answer 1

Answer:

b

Explanation:

When a hydrogen atom is in its excited level, then n = 2. Therefore radius of hydrogen atom in its first excited level (r) ∝ n2 ro ∝ (2)2 = 4ro.