Question

Bohr combined classical and early quantum concept and gave his theory in the form of three postulates.

1. The total energy of an electron in ground state of hydrogen atom is -13.6e V. What is the significance of negative sign?

2. The radius of innermost electron orbit of hydrogen atom is 5.3 × 10¹¹ m. What are the radii of n = 2 and n = 3 orbits?

Answer 1

1. Negative sign implies that the electrons are strongly bounded to the nucleus.

2. r_n = n²a₀ = 5.3 × 10^-11m
r₁ = a₀ = 5.3 × 10^-11m
r₂ = 4a₀ = 21.2 × 10^-11m
r₃ = 9a₀ = 47.7 × 10^-11m.