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/sci/ - Science & Math


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File: 120 KB, 1000x773, PeriodicTableEC-1.jpg [View same] [iqdb] [saucenao] [google]
5749645 No.5749645 [Reply] [Original]

So, all atoms want 8 valence electrons (or a full outer shell in the case of lower atomic numbers)?

How come like, the 4 shell and such can hold 32 electrons yet they never reach 8, why are't there more noble gasses?

Does this have to do with the way electron orbitals fill unevenly beyond Calcium and such?

>> No.5749658

>>5749645
>How come like, the 4 shell and such can hold 32 electrons yet they never reach 8

http://en.wikipedia.org/wiki/Krypton
[Ar], 3d10, 4s2, 4p6

>> No.5749660

the octet rule is crap, it only applies to the right 6 columns. And yes it has to do with how electrons fill orbitals, the energy of the empty orbitals of an atom determines, among other things, the bonds it can make.

>> No.5749662

They don't all want 8 electrons, just the s+p orbitals. Pic related, each orbital holds two electrons (of opposite spin), so s plus another s plus all three p is eight. Then there's an energy gap before the energies that the d orbitals, or the 3s or 2p orbitals, exist at, which is why neon is a noble gas. Understanding why they fill in the order they do takes some math though.

>> No.5749663
File: 148 KB, 1404x824, Single_electron_orbitals.jpg [View same] [iqdb] [saucenao] [google]
5749663

>>5749662
Uh pic related.

>> No.5749667
File: 13 KB, 239x250, 8009912_orig.jpg [View same] [iqdb] [saucenao] [google]
5749667

>>5749662
Better pic related.

>> No.5749693

Yo, not OP, but can someone explain to me what an oxidation number means? It seems that it's like, what ion it needs to be stable or something.

still don't got it.

>> No.5749697

http://en.wikipedia.org/wiki/Octet_rule
"(<20)"
can someone explain what happens at
>20
wat rule is that

>> No.5749707

>>5749697

d orbitals

>> No.5749722

>>5749693
>oxidation number
Looking at the periodic table you can see how many electrons an isolated neutral atom of any element should have, right?
Oxidation number tells you how many more (negative value) or fewer (positive value) electrons some atom has when considered as part of a compound or complex.
Oxidation number is largely a bookkeeping scheme, to help you keep track of how many electrons an atom 'has' in some context (ie when bonded to something else).
http://www.ilpi.com/organomet/electroncount.html
Things are a little different, and sometimes more ambiguous, when it comes to organic chemistry. When that happens we just default to some conventional agreement. (For example, in propane C3H8, are the terminal carbons in a different oxidation state as compared to the central carbon?)

>> No.5750937

So, all elements just want a full outer shell and not 8 electrons?

>> No.5750942

>>5749722
>(For example, in propane C3H8, are the terminal carbons in a different oxidation state as compared to the central carbon?)

Not OP, but why would they? Are you trying to imply they have more electron density due to more hydrogens being attached to them?

>> No.5751131

op here, still don't get it.
how do i predict compounds beyond elements 20?

>> No.5751199

After calcium (element 20), the next highest energy orbital is the 3d orbital not the 4p. The only elements you need to worry about in the 4 period is chromium and copper, where they lose a 4s electron to have 5 or ten 3d electrons. This loss of an s electron happens in all the periods in the d block but not necessarily in the same column. Palladium loses its entire 5s orbital to have a full 4d orbital. The existence of the f block is also a similar story to the d block.

d block is 3b to 2b and f block is the two separate rows at the bottum.