Q. What are the De Broglies waves?
Bohr anticipated that hydrogen's single electron could orbit at only specific distances from the atom's nucleus. When the electron is in the orbit nearest the nucleus, it has the lowest possible energy. While the electron is in the next larger orbit it has a higher energy and so on through the larger allowed orbits. The electron is able to occupy only those specific allowed orbits and therefore can have only the energies associated with those orbits. When an electron is eager by an outside input of energy it can absorb only an amount of energy needed to jump to one of the higher-energy orbits. When it falls back to a lower-energy orbit the electron emits an amount (quantum) of energy equal to the difference in energy between the two orbits. For the reason that the emission spectrum of hydrogen consisted of several different frequencies Bohr assumed that the electron could inhabit orbits of several different energies designated by integers called quantum numbers. Bohr's model of the atom sometimes called the planetary model was accepted at the time for the reason that it explained hydrogen's atomic emission spectrum. Nevertheless the model was very limited in that it only worked for hydrogen.