Question

What is the energy in joules released when an electron moves from n = 2 to n = 1 level in a hydrogen atom?

Options

• 1.635 × 10⁻¹⁸ J

• 0.750 × 10⁻¹⁸ J

• 2.906 × 10⁻¹⁸ J

• 4.361 × 10⁻¹⁸ J

Answer 1

1.635 × 10⁻¹⁸ J

Explanation:

ΔE = `2.18 xx 10^-18 (1/"n"_1^2 - 1/"n"_2^2)`

= `2.18 xx 10^-18 (1/1^2 - 1/2^2)`

= `2.18 xx 10^-18 ((2^2 - 1^2)/(1^2 xx 2^2))`

= `2.18 xx 10^-18 (3/4)`

= 2.18 × 10⁻¹⁸ × 0.75

= 1.635 × 10⁻¹⁸ J