It takes 486.0 kJ/mol to convert sodium atoms to Na + ions. Sodium atoms absorb and emit light of wavelengths 589.6 and 590.0 nm. Calculate the energy of the 590.0 nm light in kilojoules per mole.

We first calculate the energy contained in one photon of this light using Planck's equation:

E = hc/λ

E = 6.63 x 10⁻³⁴ x 3 x 10⁸ / 590 x 10⁻⁹

E = 3.37 x 10⁻²² kJ/photon

Now, one mole of atoms will excite one mole of photons. This means that 6.02 x 10²³ photons will be excited

(3.37 x 10⁻²² kJ/photon) x (6.02 x 10²³ photons / mol)

The energy released will be 202.87 kJ/mol