When an electron of an atom returns from an excited state to the ground state, it emits energy in the form of a photon. how does the change in energy level compare to the energy of the emitted photon?

a. it is less than the energy of the photon.
b. it is about one third the energy of the photon.
c. it is exactly half of the energy of the photon.
d. it is equal to the energy of the photon.
e. it is exactly twice the energy of the photon.

1. a)c-14 has two more protons

2. d)they have different numbers of protons, neutrons, and valence electrons; they are all gases at room temperature.

3. c) iron and nickel.

a. energy is absorbed in the reaction.

if in a given reaction the energy of products is greater than the energy of reactants it means that reaction is endothermic and during the reaction, the energy is absorbed by reactants. in an endothermic reaction, the products have more stored chemical energy than the reactants. and in this reaction the reactants are more stable than products before the compounds with less energy are always more stable.