Question

Radius of the first orbit of the electron in a hydrogen atom is 0.53 Å. So, the radius of the third orbit will be.

• A. 2.12 Å
• B. 4.77 Å
• C. 1.06 Å
• D. 1.59 Å

Answer 1

Answer: (B)

4.77 Å

Answer 2

$r_{n} \propto n^{2} \Rightarrow \frac{r_{3}}{r_{1}} = \frac{3^{2}}{1} \Rightarrow r_{3} = 9r_{1} = 9 \times 0.53 = 4.77Å$