Well, is the not simply a different atom, with an ext than one electron? The spectrum the helium have to be more complex, due to the fact that now angular momentum becomes a variable to which transitions room allowed; that must change by #1# every 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 the 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 for helium have actually no straightforward formula, however are known experimentally.

Using Excel, and the power levels that helium provided numerically below (estimating the #4s# and also #5s#), I"ve superposed them beside those the hydrogen:

These power level gaps are different, and also since transitions between them bring about a spectrum, the spectrum is of course also different...

To be fair, i ignored the #2p#, #3p#, #3d#, #4p#, #4d#, and #4f# power levels, which space present and also split far from the #s# level in helium (but room degenerate in hydrogen), because they room too subtle on the above scale:

That occurs since having two electrons in helium introduces electron correlation, i m sorry splits levels of various angular momentum, since they no longer have spherical symmetry.

Beyond that difference, which is easily seen in multi-electron atoms having, e.g. Orbit potential energies #V_(2s) ne V_(2p)#, #V_(3s) ne V_(3p) ne V_(3d)#, etc., we can see the adhering to trends:

The lowest power levels become lower for heavier atoms, knowing that the power levels depend straight on atomic number squared.The lowest power levels come to be more spread out from the rest, in larger atoms, obviously since bigger atoms have a greater efficient nuclear fee #Z_(eff)#, which is most conveniently seen via the most far-reaching attraction the the core energy levels (#n = 1# in both atoms).

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Because the energy level gaps widen, we expect to see shifts in electronic transitions towards lower wavelength for helium contrasted to hydrogen.

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