Atomic spectra

 Atomic spectra

Introduction:  From the JJ Thomson's Experiment we have seen that when a gas is heated, its energy increases, and this energy is seen in the form of radiation having a wide range of wavelengths if we pass this radiation through a prism we are able to see a colorful continuous spectrum which we called Atomic spectrum. In this topic, we are going to discuss the atomic spectrum of the Hydrogen atom.

When radiation from hydrogen gas was passed through a prism, the observation obtained was totally different compared to the rest of the gases. It was found that when the hydrogen gas was heated in a glass tube, very few wavelengths having certain relation among them were observed and when it was passed through a prism the spectrum obtained was not a continuous spectrum but a line spectrum.

Line spectrum

From the above diagram, we can see that the wavelength obtained from the hydrogen gas has only a certain wavelength, and the wave between the shown wavelength was missing in this spectrum. It was found that this obtained wavelength follows an empirical formula that was discovered by Balmer.

The empirical formula obtained was,

where,

𝝀 = wavelength of given line spectra

R = Reydberg's constant

m = all 𝝀integral value > 2

Spectrum series for the hydrogen atom

It was found that hydrogen emits other line spectrums ranging in the wavelength of ultraviolet rays, visible light, and near and far-infrared. The atomic spectrum series was studied by different scientists for the hydrogen spectrum. 

1) Lyman Series: Lyman series is observed in the Ultraviolet region of the spectrum

where m = 2,3,4.......

2) Balmer Series: Balmer series is observed in the visible region of the spectrum

where m = 3,4,5,.......

3) Paschen Series: Paschen series is observed in the near-infrared  region of the spectrum

where m =4,5,6,......

4) Brackett Series: Brackett series is observed in the middle infrared region of the spectrum

where m =5,6,7,......

5) Pfund Series: Pfund series is observed in the far-infrared region of the spectrum

where m =6,7,8,......

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Related Topics:  Atomic Structure      Geiger and Marsden Experiment     Atomic Spectra     Bohr's Postulate      Radius of an orbit      Velocity of an electron  Energy of an orbit      Limitation of Bohr's Model      De Broglie's explanation       Atomic Nucleus       Nuclear Binding energy        Radioactivity       Laws of radioactivity       Nuclear energy