On the off chance that one of the reactants is in overabundance yet you don't know which one it is, you have to compute the hypothetical item mass for the both reactants, with a similar item, and whichever has the lower yield is the one you use to precisely depict masses/sums for the condition, since you can't have more than the non-abundance reactant can create.
22 is a
23 is d
24 is c
I believe the answers are correct.
The 3d sublevel is not filled until after the 4s sublevel, because the 3d sublevel has more energy than the 4s sublevel, and less energy than the 4p sublevel. (:
the heat of reaction for a chemical reaction