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That depends on the ions in question. Cyanide is an excellent ligand, and will coordinate even at low concentrations. Chloride may coordinate to
copper at *waves hands* say, 1 mol/L, but it won't coordinate to nickel or manganese unless at a much higher concentration. Choride won't coordinate
appreciably to iron(II), but will coordinate readily to iron(III). Nitrate, perchlorate and sulphate won't coordinate unless the solution is so
concentrated that it no longer really qualifies as an aqueous solution.
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Beautiful; and you're proving my point about the deep nature of your experience and empirical knowledge which a newbie lacks.
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Quote: | Just as I can't know how far apart ions will stay (on average) in a liquid -- regardless of whether they are transition metals or not.
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On average, the tendency for a metal ion to be coordinated by, or at least pair up with an anion is determined by the radius of its charge to its
radius. A small and/or highly charged ion will be coordinated much more readily than a large one with a low charge. This is why the alkali metals
don't do coordination chemistry.
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I see, and that is the most useful thing you have told me so far in this thread.
Thank you!
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Hydrogen isn't an alkali metal, though- it's a non-metal, despite being in the same column as sodium.
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Yes, but think about that for a moment. Metals are classified as metals from their physical properties when crystallized; eg: conductivity, and
related reflectivity (shiny!). For it's the conductivity, when maxwells equations are solved that has a lot to do with succesfully making a mirror.
There are different ways to get conductivity, but the idea of metal .. is one where in the crystal state the molecular orbitals overlap and are only
partially filled. That means the topmost electrons are free to travel because they can "jump" to nearby energy states that are vacant. In contrast,
non conductors have a filled valence band ... but there are no empty states nearby for electrons to "jump" to. It takes significant energy, on the
order of a photon of visible light, to promote electrons in a non conductor.
No metal is really acting like a "metal" when ionized in water solution. The bands surrounding the ions are at most molecularly coupled to a handful
of very nearby water molecules. So, the important distinction has notihing really to do with being a metal and a "conduction" band ... The important
distinction is how a particular atom molecularly hybridizes it's orbitals with water or other solvents, and why.
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The H+ cation doesn't have *any* filled orbitals, so it would be orders of magnitude smaller than any ion. ... If HCl is greenish, it would be due
to electrons moving around in molecular orbitals, not the d orbitals responsible for transition metal compounds.
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Of course. I agree, that's why I pointed out 1S and 2S orbitals as being the outer unfilled orbitals involved in bonding. It's just that those are
the same shaped orbitals as the other alkalai metals, and ought to behave similarly. In the case of hydrogen, then, as an exception it DOES matter
that the chloride atom is floating nearby or at very least displacing water from contact with the hydrogen to change the color. The exact color will
depend on the quantum states which are stable in whatever solvent the hydrogen is in and the counter-ion which is near it (if any).
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I'm glad I still seem patient- my students think I've been snarling at them lately. But I hope my comments have been helpful.
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You might try starting your sentences with a different word than "no." Whether you are correcting a small mistake or a big one, the word "no" can
make a student feel like a dog or baby in a family. Once the adrenaline rushes, their ability to reason is often diminished. I realize there are
some bone headed students that you have to get their attention before they will even listed ... ADHD people ... but for your brighter students, you
might try using a less absolute opener to your corrections; eg: "not quite", or "have you thought of..."
Your comments are a very steep learning curve. In the past, I would say they have not been extremely helpful ... but that's not to say they won't
prove more useful in the future. For me, I still haven't seen copper oxide dissolve in ammonia water. I have ONLY seen it dissolve in ammonia water
exposed to air and expecially carbon dioxide. So, it's not that you are necessarily wrong ... but you've given me a contradiction to my experience
that I need to test and quantify. If something dissolves only a handful of atoms out of a gram ... that might be what you mean; but I have no way to
grasp these things without testing them.
I'm also fighting several sources of error. My scale, for example, has a hysterisses effect. I've been testing boyancy issues, water absorbtion of
air, and other reasons for my scale giving nonstandard results. BUt, after the past few days I realized that the mechanism inside is a strain guage
on a metallic bar; that guage deflects more or less depending on it's immediate past history and possibly even magnetic state. The software is pretty
good at hiding it ... but it's still giving me errors of up to 4 milligrams. So, the experiments I did in this thread need to be redone once I've
figured out ways to degauss the strain guage during operation and weighing of mass.
It's all the little things that keep biting me in the ass, that are making it difficult to isolate individual issues as is required in the scientific
method to "test one thing at a time" while keeping all others constant. It's not your comments, so much as the time it takes to isolate the issues.
[Edited on 25-1-2018 by semiconductive] |