Question

If the radius of inner most electronic orbit of hydrogen atom is , $5.3 \times 10^{- 11}$m then the radii of n = 2 orbit is

• A. 1.12 Å
• B. 2.12 Å
• C. 3.22 Å
• D. 4.54 Å

Answer 1

Answer: (B)

2.12 Å

Answer 2

As $r_{n} = n^{2}a_{0}$

Here $a_{0} = 5.3 \times 10^{- 11}m$

$n = 2$

$\therefore r_{2} = (2)^{2}a_{0}$

$= 4a_{0} = 4 \times 5.3 \times 10^{- 11}m$

$= 21.2 \times 10^{- 11}m = 2.12Å$