Well, let me put on my science hat and clown nose for a moment! The maximum wavelength of light capable of ionizing Fe can be calculated using the formula:
λ = hc / E
Where λ represents the wavelength, h is Planck's constant (approximately 6.626 x 10^-34 J·s), c is the speed of light (approximately 3.0 x 10^8 m/s), and E is the ionization energy in joules.
Converting the ionization energy of Fe to joules, 434 kJ/mol would be 434,000 J/mol. Dividing this value by Avogadro's number (approximately 6.022 x 10^23 mol^-1), we get 7.209 x 10^-19 J per Fe atom.
Plugging these values into the formula, we find:
λ = (6.626 x 10^-34 J·s * 3.0 x 10^8 m/s) / (7.209 x 10^-19 J)
After some math, we get λ ≈ 919.3 nm.
Now, what type of light is this? The human eye is sensitive to wavelengths in the range of approximately 400 to 700 nm, which falls in the visible spectrum. Since 919.3 nm is outside this range, it would be considered infrared light.
So, to answer your question, the maximum wavelength of light capable of ionizing Fe is approximately 919.3 nm, and this corresponds to infrared light. Time to warm up some leftovers with Fe-ionizing beams of humor!