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Why does hydrogen gas (molecular form) show line emission spectrum instead of band...

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cols104 | Student, Undergraduate | eNotes Newbie

Posted July 28, 2012 at 3:33 PM via web

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Why does hydrogen gas (molecular form) show line emission spectrum instead of band emission spectrum?

All particles in the atomic state show line emission spectrum and those in molecular state show band emission spectrum but why does H2 show line emission spectrum?

 

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bandmanjoe | Middle School Teacher | (Level 1) Senior Educator

Posted July 28, 2012 at 4:52 PM (Answer #1)

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Hydrogen is the simplest atom on the periodic table of elements.  It has one proton in its nucleus, surrounded by one lone electron in the first energy orbital.  Hydrogen emits a line spectrum that identifies it as the element hydrogen.  This is how the atomic contents of stars are identified, by line spectrum analysis.  But hydrogen, having only one electron in the first energy orbital, can not exist by its self in such a state.  It is one of several atoms that exist by sharing electrons between the two atomic nuclei, and are therefore called hydrogen molecules (H2).  This is why it give off a band spectrum as well, indicating the bond strength of the two hydrogen atoms as they share the two electrons between them, filling the outer energy orbital.  So hydrogen, as an atom, gives off a line spectrum, but as a molecule, it also gives off a band spectrum, as well.

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cols104 | Student, Undergraduate | eNotes Newbie

Posted July 29, 2012 at 9:11 AM (Answer #2)

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Hydrogen as a molecule give line spectrum and not band spectrum? thats my question. :)

I think you have misunderstood it.

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