Light of wavelength 242 nm ionizes a sodium ion in the gas phase; what is the ionization energy of sodium?

Question

Quizplus · Accepted Answer

The ionization energy (IE) is the energy required to remove an electron from an atom or ion. When a sodium ion is ionized by a photon of wavelength 242 nm, we know that the energy of the photon is equal to the ionization energy:

E = hc/λ = (6.626x10^-34 J·s)(2.998x10^8 m/s)/(242x10^-9 m) = 8.20x10^-19 J

To convert this energy into kilojoules per mole (kJ/mol), we can multiply by Avogadro's number (NA) and divide by 1000:

IE = (8.20x10^-19 J)(NA/1000) = 494 kJ/mol

Therefore, the answer is D, 494 kJ/mol.

Light of Wavelength 242 Nm Ionizes a Sodium Ion in the Gas