The radius of the first orbit of hydrogen atom is 0.52×10^(-8) cm. The radius of the first orbit of helium atom is

Correct answer: (A) 0.26×10^(-8) cm. r_n=(n^2)/Z0.52×10^(-8)cm For H-atom Z=1 , n = 1, r_1=0.52×10^(-8)cm For He atom, n = 1, Z = 2, r_1=1/2×0.5×10^(-8) cm =0.26×10^(-8) cm

Q27 / 99 · NTA Abhyas (JEE Main) 2020 · Chemistry · Structure of Atom

The radius of the first orbit of hydrogen atom is $0.52 \times 1 0^{- 8}$ cm. The radius of the first orbit of helium atom is

Correct answer
A
$0.26 \times 1 0^{- 8}$ cm
B
$0.52 \times 1 0^{- 8}$ cm
C
$1.04 \times 1 0^{- 8}$ cm
D
$2.08 \times 1 0^{- 8}$ cm

Solution

r_{n} = \frac{n^{2}}{Z} (0.52 \times 1 0^{- 8} cm)

For H-atom

Z = 1

, n = 1,

r_{1} = 0.52 \times 1 0^{- 8} cm

For He atom, n = 1, Z = 2,

r_{1} = \frac{1}{2} \times 0.5 \times 1 0^{- 8}

= 0.26 \times 1 0^{- 8}

Hence, the correct answer is option: 'A'.

The radius of the first orbit of hydrogen atom is 0.52×10-8 cm. The radius of the first orbit of helium atom is

Solution

More Structure of Atom Questions

The radius of the first orbit of hydrogen atom is $0.52 \times 1 0^{- 8}$ cm. The radius of the first orbit of helium atom is