mississippichem

Basically it can be seen as a result from the Pauli exclusion principle. For a given n-level the available angular momentum states, [imath] \ell [/imath], are given by [imath] n-1 \geq \ell \geq 0 [/imath]. So for lets say n=2, the available [imath] \ell [/imath] states are 1 and 0. These correspond to "s" and "p" orbitals. Thats 2+6...8 electrons. This holds for the elements in the p-block. For [imath] n > 2 [/imath] there can be higher available [imath] \ell [/imath] levels but for elements in the p-block these levels will be lower in energy than the valence [imath] \ell = 1 [/imath] levels. So the valence shell will still tend to obey the octet rule.

I loved the first Pirates of the Caribbean. After the first one, Captain Jack ceased to be mysterious and the sequels really ruined the first one for me. I hate it when a good story gets ruined by a shameless quest for cash sequel. I hope they never try to make a crappy sequel to District 9, one of my favorite recent movies. Though I fear they will.

Well for starters, there is no such thing as a hypochlorate ion. Hypochlorite is [ce] ClO^{-} [/ce] and chlorate is [ce] ClO_{3}^{-} [/ce], but there is no hypochlorate. Ethylene glycol has the formula [ce] C_{2}H_{6}O_{2}[/ce] so polyethylene glycol is some multiple of that. The calcium ion is generally found in the +2 oxidation state.

Though I'm sure they will try. The IUPAC seems to always have too much to say about everything.

That, and it is much easier to write down a matrix in 4-space, or to find a linear combination of 4-vectors than it is to try and visualize 4 dimensions. It would be faster to just take a linear algebra course than it would be to sit here now and try to visualize four dimensions. Our intuition is based on our experience. All our experience takes place in [math] \mathbb{E}^{3} [/math] at [math] \vec{v} <<c [/math] so intuition doesn't help much in relativistic situations. Once again math becomes the key to understanding. I could write a book... Even though math seems cryptic to many, it really makes life much easier.

I would hardly call the above example "advanced mathematics", definitely not elementary but not advanced. Special relativity has the great property of being able to be understood with relatively little (pardon the pun) math, when compared to general relativity. If you do not understand the above calculation, then you are really not qualified to make many statements about relativity. It doesn't bother me more than slight bewilderment, but you are doing yourself a huge disservice by trying to comprehend these things without the mathematics. It is analogous to trying to understand English literature while only speaking japanese, a hamster wheel type task. Special relativity appears to be magical and mythical to you because you don't understand the mathematical foundation. The human brain is not capable of keeping track of all these factors qualitatively, no one is that intelligent and no one has that much computational power. That's why we have to use the mathematics to understand many of these complex problems of physical science. Cap'n Refsmmat's above calculation was all derived from first principles. Straight out of basic SR, Newton, and simple geometry (except for the Stefan-Boltzmann constant...yeah, yeah) where is the magic?

Are you going to want to denature the proteins containing the selenomethionine first? What I'm really asking is, are you going to do all the standard biochemical isolation procedures first, or are you going to try and run AAS on the crude cell samples? This would obviously depend on if you want to look at total selenium or specifically selenomethionine selenium.

You still have to explain the close to nil result obtained on Earth.

I imagine we'll be needing crude oil or natural gas as an organo-polymer feedstock for at least the next couple of hundred years if not longer. Making alkanes from scratch [black carbon and H2] is just not economically viable on a large scale.

Wait!? Weren't you the guy bashing fundamentalists for believing in talking snakes and burning bushes? You can't be serious, surely you jest. At least some fundamentalists realize that their beliefs are irrational and only faith based. You actually believe that eye witness accounts are worth a damn, and personal [first person] accounts at that. I used to have friends in college that believed in telepathy...its accessed through technique called eating LSD, i.e. it only happens when you are tripping or insane. Your "more skeptical than thou" attitude is quite perplexing given that you believe in telepathy. If you believe in that, why not believe in Satan embodied as a talking serpent 7000 years ago in the garden of Eden? I don't believe either, and I think they are both about on the same order silliness. Another funny thing is that though you bash fundamentalists, you defend your position just like a fundamentalist; by repeating yourself over and over without any real logos.

Perchlorates have a stronger oxidation potential but chlorates oxidize much more readily (low activation barrier IIRC). I would be more than cautious around an aluminum powder/KClO3 mix.

Sounds like Gnome trickery to me. Gnome Physics, by Cap'n Refsmmat

Greatest I am: The Christians and Jews have absolutely no proof of the existence of Yahweh and the Muslims have no proof of Allah. How is your belief in a "Godhead" any more rational than their belief in an anthropomorphic deity. The "religious" claim that God exists and has a role to play in our lives. You claim that a godhead exists and basically does nothing and has no interaction with us. How is that any more reasonable? I have a pet fairy, you can't see her, she doesn't violate any natural laws, and you can in no way experience her. All discussions of her are speculative nonsense, however, I assure you that she exists.

I forgive you. If you are like me, your competence depends exponentially on your blood caffeine concentration. This function has a local max though, too much caffeine, and I degrade back into a babbling idiot .

Hmm...My knowledge of Hilbert spaces doesn't extend much beyond their use in QM (Schroedinger equations must be continuous and square integrable...etc. If memory serves). Care to elaborate at all? What kind of Hilbert space are we talking about here? My analysis chops are limited but bring it on anyway, I'll try to hang .

This isn't something I know much about but here is a PDF that you guys should find interesting. http://aerosol.ucsd.edu/classes/sio217a/sio217afall08-myth1970.pdf It has a list of "global cooling" and "global warming" papers from 1965 to 1975 with numbers of citations; no idea if the list is exhaustive. It appears that there was in fact some peer reviewed literature that embraced "global cooling" at the time. However they seem to be outnumbered and out-cited by the global warming papers in significant numbers. It appears that JohnB and you, swansont, are both correct in a way.

This is by far my favorite: (Courtesy of the nerds at IBM) This is an atomic force microscopy image of pentacene. Truly striking! The problem with this technique is, it only works well for somewhat planar molecules with a lot of resonance. So you can see the resemblance, here is the bond line formula for pentacene. It's nice to finally see a molecule with it's geometry. It is really nice to know that NMR, and X-ray diffraction are in fact correct! I would say that the Hubble Deep Field image is a very close second for me! I like images of the ridiculously small as well as the inconceivably large.

Thats a funny story. If people knew how dilute that urine would've been by the time it reached their glass of water then the city could have saved $36,000! The joy of chemistry is knowing that there is probably at least a few molecules of everything in just about anything. A sensitive enough mass-spec might be able to find some uranium in your morning coffee.

hypervalent_iodine already addressed this but I thought I would say it again in a different way to further get the point across: We already know how to make the illicit substances you might be trying to make! Trying to disguise your project as something else will not get past us. We had a poster not too long ago who was clearly to trying to gain the necessary knowledge to synthesis crystal methamphetamine [a stimulant that is illegal in the US, most of Europe, and many other places]. Before that post could receive any helpful response, myself and the other other regular chemistry "instructors" around here jumped on it. All this to say. Don't even try if your intentions are dubious, illicit, or shady. You can't fool us. Feel free to ask for legitimate help any time though, just be on the up and up about it. Science can be a dangerous hobby.

The photons that enter the eye get refracted by the lens and then come into contact with various biochemicals in the rod and cone cells in the retina. Those photons excite electrons in these various bio-molecules [i.e. are absorbed]. So you are right, the photons that enter do not exit, but not for the reason you posit.

If a salt is still hot, then it may be losing crystallization waters as it cools which can change the weight of the sample significantly. The reverse can also happen if you put some very hygroscopic chemical on a scale exposed to air for a while (especially if you live in a humid climate like me). I've never seen it, but I've heard you can throw a bit of tetra-n-butylammonium chloride on the scale and watch the sample gain mass over the course of a few minutes. I'm sure safety is also a factor though as very much don't won't to get covered in hot wet salt! EDIT: hypervalent_iodine: We posted almost at the same time. I beat you by about thirty seconds with the same answer. I win

We've made stable compounds of most of the noble gases, but helium and neon have only produced short lived cationic species like [ce]HeH^{+}[/ce] as far as I know. There's just no appreciable effective nuclear charge on the outer shell and the average radius is not sufficient enough to allow for enough polarization to get some of "Van der Waals-ish" complexes you can get with the heavier noble gases. That and for helium you usually get a scenario where any bond that forms will have a quite highly occupied anti-bonding orbital which is no good.

Which oxidation numbers? Many of them have many common oxidation states, for example manganese takes on oxidation states from Mn(0) to Mn(VII).

Do some reading about metal to ligand charge transfer MLCT, and ligand to metal charge transfer LMCT. You would also do well to read a bit about cyclic voltammetry and UV-vis spectroscopy which are used to observe these types of charge transfers. This topic is a quite complicated one in chemistry. Do a little reading and get back to us soon. I can help once you've had a small amount of background reading. It would be too cumbersome to explain in a post.