<span> The energy of wave if it has a wavelength of 3.0 </span>× <span>10⁷ nm is
6.26 </span>
× 10⁻²⁴ J.
Attached below, is how to derive that answer. Note that, E= Energy, λ = wavelength, h = Plank's Constant and C= speed of light
Also, I converted the wavelength from nm to cm.
(2) argon. This is because Ca originally has 20 total electrons with a configuration of 2,8,8,2. When it looses its valence electrons it remains with 18 electrons total (2,8,8 config). Argon has 18 electrons total too (2,8,8 config).