Heavy elements emit characteristics X-ray when their electrons undergo transitions. Shown below are the wavelengths of x-rays emitted by some elements:

Element          Wavelength (Å)
Cr                     2.291
Fe                     1.937
Co                    1.790
Cu                    1.542
Mo                    0.7107 

If a particular element emits an X-ray with a wavelength of 1.662 Å, determine the identity of the element. Hint: Plot the square root of ν versus the atomic number of the element.