Question 16 of 62intermediate🔧 ApplyNumerical2 marks

(i) The energy associated with the first orbit in the hydrogen atom is –2.18×102.18 \times 10⁻¹⁸ J atom⁻¹. What is the energy associated with the fifth orbit? (ii) Calculate the radius of Bohr’s fifth orbit for hydrogen atom.

(i)
Answer

−8.72×10−20-8.72 \times 10^{-20} J atom−1^{-1}

(ii)
Answer

1322.5 pm

Explanation

The energy of an electron in the nthn^{th} orbit of a hydrogen atom is given by En=−RH(1n2)E_n = -R_H \left( \frac{1}{n^2} \right), where RH=2.18×10−18R_H = 2.18 \times 10^{-18} J. The radius of the nthn^{th} orbit is given by rn=n2a0r_n = n^2 a_0, where a0=52.9a_0 = 52.9 pm. By substituting n=5n = 5 into these formulas, we can find the energy and radius of the fifth orbit.