Isn't there some hand-waving going on here? The outer orbital is being treated as the last la...

robocat • yesterday at 7:47 PM • 4 replies • view on HN

Isn't there some hand-waving going on here?

The outer orbital is being treated as the last layer of an onion and the atoms are "inside" that. But orbitals are not spherical so our geometrical intuitions kinda fail.

Edit: Sorry for unclear wording: well, s-orbitals are spherical overlapping probability clouds, but they are not shells like an onion. Nor are they spheres as we commonly think of the geometrical object. To say something is "inside" a probability cloud gets difficult. Disclaimer: my memory/understanding of physics/chemistry/probability is poor. Edit 2: when orbitals of atoms overlap for molecules, don't the orbitals get funkier shaped probability distributions? Surely the same thing happens here and the cloud shapes would change - orbitals are not independent things you can just smoosh together or overlap willy-nilly due to qwuantum blah blah.

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robocat • yesterday at 11:19 PM

So I thought of a nice question: how close-in does the hydrogen in Rubidium Hydride sit. For gaseous RbH and thinking in solid spheres instead of clouds:

  The bond length of RbH is ~4.5 units.

  The Hydrogen proton is *inside* the empty 5s radius (~4.7 units).

  If we added an electron ("an antibonding electron") it would go into the 5s orbital. But that stretches the bond making the distance between the nuclei ~4.8 units.

  In RbH, the Rb atom gives up its single outer 5s electron to the H atom, so there is no populated 5s electron shell in a Rubidium Hydride molecule.

hatthew • today at 3:24 AM

A little bit of hand waving, but I don't mind it much. A cloud of steam rising from a boiling pot doesn't have a well defined border or consistent shape, but a human looking at a nearby object can usually make a clear and reasonable decision about whether or not that object is "inside" the steam cloud.

alt Hacker News

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