NS FL3 chm/phys Q13

vgp1993
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Joined: Wed Dec 20, 2017 12:14 pm

NS FL3 chm/phys Q13

Postby vgp1993 » Sun Apr 22, 2018 10:34 am

"Which of the following types of electromagnetic radiation would have the shortest wavelength?"

I was having some trouble following the explanation for this question, so I was wondering if someone could break it down a little bit further.


Thanks!
NS_Tutor_Andrew
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Posts: 520
Joined: Mon May 23, 2016 1:47 pm

Re: NS FL3 chm/phys Q13

Postby NS_Tutor_Andrew » Tue Apr 24, 2018 11:49 am

Hi vgp1993,

There are basically two parts to this question: figuring out what they're getting at re: electron orbitals and then linking that to wavelength. Turning to the orbitals, the idea is that electrons in s orbitals (or more "s-like" hybrid orbitals) are held more tightly to the nucleus and therefore would require more energy to eject. Based on this realization, we can determine that we need to look for the highest-energy photon (or EM radiation), and the Q asks us to think in terms of wavelength. The key equations here are (1) E = hf, (2) c = λf, and (3) the combination of those two equations E = hc/λ. (Parenthetically, these are right up there with F = ma as essential physics equations for the MCAT -- students sometimes lose track of this fact because it feels like physics 1 content should be more important, but that's not actually the case). The MCAT can ask you to use these equations numerically, but also tests them conceptually -- higher energy is associated with a higher frequency, which is equivalent to a lower wavelength. Putting these pieces together, the smallest-wavelength EM radiation will have the highest frequency and the most energy, and the most energy will be needed to eject an electron from an sp orbital.

Hope this helps clarify the question!
Andrew D.
Content Manager, Next Step Test Prep.

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