Definition:
Is a definite series of lines and colours resulted when an electric discharge is passed through hydrogen gas in the emission tube under very low pressure.
The H – spectrum is recorded in the
spectrographic plate.
The horizontal diagram of H-spectrum
The explanation in terms of atomic structure:-
First band:
Is a colourless band or invisible band. These are spectrum produced by the electrons excited from the first shell.
Electrons from the first shell experience stronger nuclear
attractive force such that high energy is required in order to jump toward the highest energy level. When these electron returned back release high amount of energy of shorter wave lengths. These wavelengths can not be detected by a human eye. The radiation formed are continuous spectrum
such as X – ray, sun rays etc.
Second band:
Is a visible band which has a definite line and colour. These are line spectra, produced by electrons excited from the second shell. The electrons in the second shell need moderate energy to jump toward the highest energy level when return back release normal energy with the wave length detected by a human eye.
Third band:
Is invisible band. These spectra are colourless having no definite lines.
The electrons that produce these spectra cause the scattered spectrum which appear as a colourless band. This is due to the lowest energy and highest wave length.
The vertical diagram of H-spectrum.
Explanation:
Lyman series:
Is a series of spectrum resulting from electrons excited from the first shell (n=1).
These series correspond to the invisible band or colourless band.
Balmer series:
Is a series of spectrum resulting from electrons excited from the
second shell (n = 2).
This corresponds with visible or violet band.
Paschen’s series:
Is a series of spectrum resulting from electrons exited from the third
shell (n = 3) etc.
Bracket series:
Is a series of spectrum resulting from electrons excited from the forth
shell (n = 4) etc.
p-fund series:
Is a series of spectrum resulting from electrons exited from the
fifth shell (n=5).
PLANCK’S QUANTUM THEORY
"Planck is considered the father of the quantum theory"
Planck postulated the quantum theory.
ii. The energy is released in the form of radiation, that occurs in small discrete packets called quanta.
iii.The energy is directly proportion to the frequency of radiation.
Implication of the plank's quantum theory
Energy of light is proportional to the frequency
E∝f
The constant relating these two above is the planck's constant.
Symbol (h)
E = hf………………….....(1)
Since; h = Planck’s constant
h = 6.63 x 10 -34 Js
n= 1
Since f = c/λ
E = hc/λ…………....…….(2)
c = 3.0 x 10^-8 ms^-1
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Is a definite series of lines and colours resulted when an electric discharge is passed through hydrogen gas in the emission tube under very low pressure.
The H – spectrum is recorded in the
spectrographic plate.
The horizontal diagram of H-spectrum
The explanation in terms of atomic structure:-
First band:
Is a colourless band or invisible band. These are spectrum produced by the electrons excited from the first shell.
Electrons from the first shell experience stronger nuclear
attractive force such that high energy is required in order to jump toward the highest energy level. When these electron returned back release high amount of energy of shorter wave lengths. These wavelengths can not be detected by a human eye. The radiation formed are continuous spectrum
such as X – ray, sun rays etc.
Second band:
Is a visible band which has a definite line and colour. These are line spectra, produced by electrons excited from the second shell. The electrons in the second shell need moderate energy to jump toward the highest energy level when return back release normal energy with the wave length detected by a human eye.
Third band:
Is invisible band. These spectra are colourless having no definite lines.
The electrons that produce these spectra cause the scattered spectrum which appear as a colourless band. This is due to the lowest energy and highest wave length.
The vertical diagram of H-spectrum.
Lyman series:
Is a series of spectrum resulting from electrons excited from the first shell (n=1).
These series correspond to the invisible band or colourless band.
Balmer series:
Is a series of spectrum resulting from electrons excited from the
second shell (n = 2).
This corresponds with visible or violet band.
Paschen’s series:
Is a series of spectrum resulting from electrons exited from the third
shell (n = 3) etc.
Bracket series:
Is a series of spectrum resulting from electrons excited from the forth
shell (n = 4) etc.
p-fund series:
Is a series of spectrum resulting from electrons exited from the
fifth shell (n=5).
PLANCK’S QUANTUM THEORY
"Planck is considered the father of the quantum theory"
Planck postulated the quantum theory.
The theory has three main points;i. Any radiation should be associated with energy.
ii. The energy is released in the form of radiation, that occurs in small discrete packets called quanta.
iii.The energy is directly proportion to the frequency of radiation.
Implication of the plank's quantum theory
Energy of light is proportional to the frequency
E∝f
The constant relating these two above is the planck's constant.
Symbol (h)
E = hf………………….....(1)
Since; h = Planck’s constant
h = 6.63 x 10 -34 Js
n= 1
Since f = c/λ
E = hc/λ…………....…….(2)
c = 3.0 x 10^-8 ms^-1
Back/Next
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