Chapter 6, Problem 6.95PAE

6.95 A metallic sample is known to be barium, cesium, lithium, or silver. The electron binding energies for these metals are listed in the following table.

Metal Electron Binding Energy(J)

Barium    $4.30\times {10}^{-19}$ Cesium    $3.11\times {10}^{-19}$ Lithium    $3.94\times {10}^{-19}$ Silver    $7.59\times {10}^{-19}$

One way to identify the element might be through a photoelectric effect experiment. The experiment was performed three times, each time using a different laser as the light sources. The results are summarized below. (The Kinetic energy of the ejected photoelectrons was not measured.)

Laser Wavelength Photoelectrons Seen?

532 nm No 488 nm Yes 308 nm Yes

Based on this information, what conclusions can be drawn as to the identity of the metal?