Radius of the first excited state of Helium ion is given as : a0 → radius of first stationary state of hydrogen atom.

Question

Radius of the first excited state of Helium ion is given as :

\(a_0 \rightarrow\) radius of first stationary state of hydrogen atom.

(1) \(r = \frac{a_0}{2}\)

(2) \(r = \frac{a_0}{4}\)

(3) \(r = 4a_0\)

(4) \(r = 2a_0\)

Answer 1

Correct option is:  (4) \(r = 2a_0\)

\(r = a_0 \frac{n^2}{Z} = a_0 \times \frac{2^2}{2}\)

\(r = 2a_0\)