Well, is it not just a different atom, via more than one electron? The spectrum of helium should be even more facility, bereason now angular momentum becomes a factor to which transitions are allowed; it should 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 power levels of the hydrogen atom are well-known:

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

where #Z = 1# for hydrogen atom.

You are watching: Why are the emission wavelengths for helium and hydrogen different

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

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

*

These power level gaps are different, and also considering 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 also #4f# power levels, which ARE current AND split ameans from the #s# levels in helium (but are degenerate in hydrogen), bereason they are too subtle on the over scale:

*

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

Beyond that distinction, 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)#, etc., we have the right to see the following trends:

The lowest power levels become lower for heavier atoms, understanding that the power levels depend straight on atomic number squared.The lowest power levels come to be even more spreview out from the remainder, in larger atoms, obviously because bigger atoms have actually a greater efficient nuclear charge #Z_(eff)#, which is a lot of conveniently seen by means of the the majority of significant attraction of the core energy levels (#n = 1# in both atoms).

See more: True Or False: Shopping Ads Use Merchant Center Product Data To Decide How And Where To Show Ads.

Since the power level gaps widen, we intend to watch shifts in electronic transitions towards lower wavelength for helium compared to hydrogen.

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