The law which says that matter is neither produced nor destroyed in a physical or chemical reaction is the law of

The problem here is that according to aufbau principle before 3d orbital 4s subshell comes.after filling 3p orbital with electrons you have 4 electrons left, you place two in 4s with opposite spin and the other two in 3d in any of its two orbitals of total five orbitals with the same spin.

Ireally don’t know this

Green is technically every other color but green but the other wavelengths of the other colors get absorbed by the object and the wavelength of the color green gets reflected