Bohr, are quite complicated and will be discussed in higher classes. However, according to Bohr’s theory for hydrogen atom: a) The stationary states for electron are numbered n = , , .......... These integral numbers (Section . .
) are known as Principal quantum numbers . b) The radii of the stationary states are expressed as: r n = n a ( . ) where a = . pm.
Thus the radius of the first stationary state, called the Bohr orbit , is . pm. Normally the electron in the hydrogen atom is found in this orbit (that is n = ). As n increases the value of r will increase.
In other words the electron will be present away from the nucleus. c) The most important property associated with the electron, is the energy of its stationary state. It is given by the expression. E H R n = , , ....
( . ) where R H is called Rydberg constant and its value is . × – J. The energy of the lowest state, also called as the ground state, is E = – .
× – ( ) = – . × – J. The energy of the stationary state for n = , will be : E = – . × – J ( ) = – .
× – J. Fig. . depicts the energies of different stationary states or energy levels of hydrogen atom.
This representation is called an energy level diagram. When the electron is free from the influence of nucleus, the energy is taken as zero. The electron in this situation is associated with the stationary state of Principal Quantum number = n = ∞ and is called as ionized hydrogen atom. When the electron is attracted by the nucleus and is present in orbit n, the energy is emitted and its energy is lowered.
That is the reason What does the negative electronic energy ( E n ) for hydrogen atom mean? The energy of the electron in a hydrogen atom has