Red light has a wavelength of 700 nm, and a frequency of 4.3*1014 Hz. Visible light makes up just a small part of the full electromagnetic spectrum. Electromagnetic waves with shorter wavelengths and higher frequencies include ultraviolet light, X-rays, and gamma rays.
The Energy of an atom that emits a photon of wavelength 2.21 m is
3.028 × 10⁻¹⁹ J.I attached the working and the answer to the question below. I hope I was able to help.
Please note that C = speed of light, ν = frequency, λ= wavelength, h = Planck's Constant
<span>The metal that would more easily lose an electron would be potassium. It is more reactive than sodium. Also, looking on the periodic table, </span><span>from top to bottom for groups 1 and 2, reactivity increases. So, it should be potassium. Hope this answers the question. Have a nice day.</span>