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Excited energy level

  1. Apr 7, 2006 #1
    A sample of hydrogen gas absorbed sufficient energy to make the electrons jump to the 3rd excited energy level. It is said that 6 lines can be observed in the complete emmission spectrum as the atoms relax back to ground state.

    But why six though?

    When I check a diagrm of the spectrum, it will have infinity of spectrums, and 1-5 will be visible, while the sixth one visible is the last line, the infinity line. However is my line of thought correct? Because it only states that the electrons jump to the 3rd electron level and the atom relaxes back to ground state, so I thought it suppose to be 3 visible lines then.

    I am really confuse now:surprised !
    Please help!

    Thanks in advance
  2. jcsd
  3. Apr 9, 2006 #2


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    Read about selection rules in your text.
  4. Apr 9, 2006 #3


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    From the 'third' excited state, what are the possible transitions? Note that there are two excited states, and the ground state at lower energies.
  5. Apr 9, 2006 #4
    Thanks for the reply,

    I have checked my textbook, and it rarely talked about this spectrum (1page out of 1123 pages). And this question I got it from my practice final, from which the answer said it was six.

    Yeah, i was thinking about that too, and then it should be three then, right?
    But the solution in the practice final says it was six.

    Many thanks for the reply guys!
  6. Apr 9, 2006 #5


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    There are three states below the 'third' excited state.

    Denote 0 as ground state, and 1, 2, 3 as excited states. There are three possible de-excitations to ground state - so that's 3.

    What are the other possibilities? Each excited state represents an energy level.
  7. Apr 10, 2006 #6
    So then, do you count the excited state as one and de-exitications as another?

  8. Apr 12, 2006 #7


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    Transitions can occur between excited states - e.g. 3-2 - in addition from excited to ground.

    The spectrum of hydrogen has different groups of emission/absorption lines, including Lyman (UV), Balmer (visible) and Paschen (infrared)

    The Lyman series represents transitions from excited states (n>1) to the ground state (n=1), the Balmer series represents transitions from excited states (n>2) to the first excited state (n=2), and the Paschen series from excited states (n>3) to 2nd excited state (n=3). n is the principal quantum number for atomic electrons.
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