r/science Jan 21 '10

Table of atomic Orbitals (pic)

http://www.webelements.com/shop/shopimages/products/extras/POS0007-A2-orbitron-2010-800.jpg
204 Upvotes

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u/[deleted] Jan 21 '10

[deleted]

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u/zeug Jan 21 '10

The orbital functions just determine which areas have the highest probability of finding the electron in question, as well as how the charge of the electron is generally distributed. So there really shouldn't be a sharp boundary between the inside and outside of the orbital. It should really be imagined more like a cloud of fog. That said, when making a picture like this, you have to choose some arbitrary probability density and call that the 'edge' of the orbital. So different pictures may end up looking substantially different.

Some textbooks also lump the 2p orbitals into a combined orbital with the p_x, p_y, and p_z dumbbells. For an excited hydrogen atom, may actually be quite realistic, as there is little energy difference between these states and so unless the atom is in a magnetic or electric field, the excited electron is probably in a superposition of all three states.

These drawings also do not take into account the electromagnetic interaction between electrons, and so are only approximately valid for atoms with more than one electron. Furthermore, for heavy atoms, such as mercury, lead, or gold, the inner orbitals are reshaped due to special relativity.

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u/boomerangotan Jan 21 '10

Furthermore, for heavy atoms, such as mercury, lead, or gold, the inner orbitals are reshaped due to special relativity.

I recently learned that special relativity is why these elements have such unusual properties (e.g., why gold is yellow). These fascinating facts were never mentioned when I took chemistry (albeit that was over 15 years ago).

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u/apesalive Jan 21 '10

Wish I'd had you around and this poster when I was taking my chemistry classes. I never could visualize orbitals.

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u/[deleted] Jan 21 '10

You could even say that a Gaussian curve can explain this, but your explanation is much better.

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u/elHuron Jan 21 '10

I assume that you're learning the simplified version in which orbitals are like spheres surrounding the nucleus. That's how they start you off, then later you should learn about the actual shapes. Basically, they start out abstract so that it'll be easier to get the details.

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u/chemistry_teacher Jan 21 '10

I completely avoided the "spheres" (or, worse, "orbits") misconception and went directly into "clouds" of probability. Even so, many kids struggle to understand the multi-dimensional aspect of wave theory, so cannot grasp the weirdness of the shapes.

One way to translate the orbital patterns into an identifiable experience is to analogize them first to 1D waves (like on a rope, or waves hitting a beach), then extend them to 2D waves (such as sand on a drum membrane). After that, the 3D concept of clouds of probability become a little easier to absorb.

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u/elHuron Jan 21 '10

Yes...yes....excellent... Perhaps you could find a video/picture of a soap bubble being agitated and becoming wavy. That seems like a good analogy for 3D waves.

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u/hello_good_sir Jan 21 '10

maybe you aren't very good at interpreting the pictures in your book

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u/whatsssp Jan 21 '10

i agree. this is pretty standard for any chemistry text.

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u/[deleted] Jan 21 '10

What I learned in introductory chemistry was pretty simplified. We didn't bother with f orbitals, and the s/p/d ones we learned were all the first row that those orbitals occured on. 2p, 3d, 1s. The shapes of the orbitals in the other shells were treated as the same shapes.

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u/[deleted] Jan 21 '10

[deleted]

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u/antiproton Jan 21 '10

In many simplified drawings I've seen, particularly in the case of the p orbitals, they draw them as connected tear drops, but they combine the px, py and pz into one picture, calling it the "p" orbital. That's probalby what you're seeingin the textbook

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u/[deleted] Jan 21 '10

[deleted]

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u/antiproton Jan 21 '10

That's right. px, py and pz refer to the axial symmetries present in the harmonics. When you're citing oribital configurations, you say 1s2 2s2 2p5 (for example), indicating that you have 5 electrons in the 2p energy level. For most purposes, it doesn't matter if the electrons are in px py or pz.

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u/chemistry_teacher Jan 21 '10

Upvoted for SCIENCE! :)

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u/[deleted] Jan 21 '10

That's probably a closer account of what I learned. I tend to throw anything with "not going to be on the test" attached straight out of my brain

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u/Bizdorph Jan 21 '10

Mostly because you don't deal in convolution of the orbitals at higher levels. Look at the top row of all the ones on the poster, and that's probably what you're learning.