when the elements mg and cl form an ionic bond, mg loses electron(s) from the 3s orbital to form the mg2 cation. cl gains electron(s) in the 3p orbital to form the cl– anion. since the total number of electrons lost always equals the total number of electrons gained, the compound formed will contain mg2 ions) for every cl– ion(s). fill in the blanks with the appropriate numbers.

correct it is c.) b b

i think it would be 5

you'd use the equation that establishes a relationship between  energy  and  wavelength, which looks like this

e=h⋅cλ, where

λ  - the wavelength of the photon; c  - the speed of light, usually given as  3⋅108m/s; h  -  planck's constant, equal to  6.626⋅10−34j s

plug the value you were given for the energy of the photon in the above equation to get the wavelength

e=h⋅cλ⇒λ=h⋅ce

λ=6.626⋅10−34js⋅3⋅108ms−1.257⋅10−24j=1.581⋅10−1m