Answer:
In 1913, Niels Bohr proposed a theory for the hydrogen atom, based on quantum theory that some physical quantities only take discrete values. Electrons move around a nucleus, but only in prescribed orbits, and if electrons jump to a lower-energy orbit, the difference is sent out as radiation.
Answer:
releases, increase
Explanation:
The total energy of products in an Exothermic reaction is less compare to
total energy of the reactants. As a result of these the enthalpy becomes negative, then there is release of heat to the surroundings, which increase the energy of the immediate surroundings inform of heat. Hence the system release energy while the surroundings energy increase.
The valence electrons is last outer shell of an atom. So it is the last number of the electron configuration on the periodic table.