The threshold frequency ( 0 ) that can dislodge an electron from metallic sodium is 5.51

The threshold frequency (ν₀) that can dislodge an electron from metallic sodium is 5.51 × 10¹⁴ s^-1.

(a) What is the energy, in joules, of a photon with frequency of ν₀?

(b) What is the energy, in joules, of a photon with a wavelength of 430.0 nm ?

(c) What is the kinetic energy, in joules, of an electron that is ejected from sodium by light with a wavelength of 430.0 nm?

(d) What is the energy (in kJ/mol) of a mole of photons with frequency of ν₀?

Strategy

(a) Use Planck’s relationship between energy and frequency to determine the energy of the photon.

(b) Use the relationship between c, λ, and ν to first determine the frequency of the photon, then Planck’s relationship to determine its energy.

(c) Use Einstein’s relationship between E and the threshold frequency ν₀ to determine the kinetic energy of the ejected electron.

(d) Multiply the energy of one photon by Avogadro’s number and convert to kJ to determine the energy of a mole of photons having a frequency of ν0.