Well, is it not just a different atom, via more than one electron? The spectrum of helium need to be more facility, because now angular momentum becomes a factor to which transitions are allowed; it should readjust by #1# each time.

Examples:

#1s -> 2p# (#"58.4 nm"#)#2s -> 3p# (#"501.6 nm"#)#2p -> 4d# (#"492.2 nm"#)#2p -> 4s# (#"504.8 nm"#)

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The power levels of the hydrogen atom are well-known:

#E_n = -"13.6058 eV" cdot Z^2/n^2#

wbelow #Z = 1# for hydrogen atom.

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Those for helium have actually no straightforward formula, but are recognized experimentally.

Using Excel, and also the energy levels of helium offered numerically right here (estimating the #4s# and also #5s#), I"ve superposed them beside those of hydrogen:

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These power level gaps are different, and given that transitions in between them result in a spectrum, the spectrum is of course also different...

To be fair, I ignored the #2p#, #3p#, #3d#, #4p#, #4d#, and #4f# energy levels, which ARE current AND break-up away from the #s# levels in helium (yet are degenerate in hydrogen), bereason they are too subtle on the above scale:

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That occurs bereason having actually two electrons in helium introduces electron correlation, which splits levels of various angular momentum, bereason they no longer have actually spherical symmetry.

Beyond that difference, which is readily viewed in multi-electron atoms having, e.g. orbital potential energies #V_(2s) ne V_(2p)#, #V_(3s) ne V_(3p) ne V_(3d)#, and so on, we deserve to check out the following trends:

The lowest power levels end up being lower for heavier atoms, knowing that the power levels depfinish straight on atomic number squared.The lowest energy levels end up being more spread out from the remainder, in larger atoms, obviously because bigger atoms have a greater efficient nuclear charge #Z_(eff)#, which is many easily watched through the the majority of significant attraction of the core energy levels (#n = 1# in both atoms).

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Due to the fact that the power level gaps widen, we mean to check out shifts in digital transitions in the direction of lower wavelength for helium compared to hydrogen.

(Indeed, the #1s -> 2s# change is #"58.4 nm"# for helium compared to #"121.5 nm"# for hydrogen.)