Well, is the not simply a different atom, with an ext than one electron? The spectrum of helium need to be more complex, because now angular momentum i do not care a element to i m sorry transitions space allowed; the must adjust 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"#)

The energy levels that the hydrogen atom space well-known:

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

where #Z = 1# for hydrogen atom.

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Those because that helium have no straightforward formula, however are well-known experimentally.

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

These power level gaps are different, and also since transitions in between them lead to a spectrum, the spectrum is of course additionally different...

To it is in fair, ns ignored the #2p#, #3p#, #3d#, #4p#, #4d#, and #4f# energy levels, which space present and split far from the #s# level in helium (but space degenerate in hydrogen), because they room too ethereal on the over scale:

That occurs because having 2 electrons in helium introduce electron correlation, which splits levels of different angular momentum, due to the fact that they no longer have actually spherical symmetry.

Beyond the difference, i beg your pardon is easily seen in multi-electron atoms having, e.g. Orbital potential energies #V_(2s) ne V_(2p)#, #V_(3s) ne V_(3p) ne V_(3d)#, etc., we have the right to see the complying with trends:

The lowest power levels become lower because that heavier atoms, knowing that the power levels depend directly on atom number squared.The lowest energy levels become more spread out from the rest, in larger atoms, obviously because bigger atoms have a greater reliable nuclear fee #Z_(eff)#, i beg your pardon is most easily seen via the most far-ranging attraction the the core power levels (#n = 1# in both atoms).

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Because the energy level gaps widen, we suppose to check out shifts in electronic transitions in the direction of lower wavelength for helium compared to hydrogen.

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