Question

The ionization energy is the energy needed to remove an electron from an atom. In the bohr model of the hydrogen atom, this means exciting the electron to the n = ∞ state. What is the ionization energy in kj/mol, for hydrogen atoms initially in the n = 2 energy level?

Answer 1

The ionization energy for a hydrogen atom in the n = 2 state is 328 kJ·mol⁻¹.

The first ionization energy of hydrogen is 1312.0 kJ·mol⁻¹.

Thus, H atoms in the n = 1 state have an energy of -1312.0 kJ·mol⁻¹ and an energy of 0 when n = ∞.

According to Bohr, Eₙ = k/n².

If n = 1, E₁= k/1² = k = -1312.0 kJ·mol⁻¹.

If n = 2, E₂ = k/2² = k/4 = (-1312.0 kJ·mol⁻¹)/4 = -328 kJ·mol⁻¹

∴ The ionization energy from n = 2 is 328 kJ·mol⁻¹ .