The Periodic Table - 2016-10-15 (page 2 of 2)

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9:00 AM

imgur.com/a/E82bo

imgur.com/gallery/smUnLU2

@pH13-YetanotherPhilipp it's not that bad

@Hippalectryon 6 months doesn't sound so terrible. It builds character. ;-) And it's not la Légion étrangère.

@Loong Some other students go there >.>

wow

pH13 - Yet another Philipp

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9:11 AM

In the army, I was the "commander" of a 2.5 ton truck, used a GC-MS in an NBC tank, or decontaminated vehicles.

Imaging Loong on a truck

@Rubisco For future reference, I type this message containing the word "pedantry" and "nervous" to be able to find that message later.

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@Rubisco like this one

It's a bit difficult when you go to a McDonalds drive-in since it is so high.

pH13 - Yet another Philipp

@Loong but I guess it’s funny

@Loong You can always grab the sandwich with your toes

@Loong Ah yeah I've used those too :D they're not fun when you brake hard though

9:20 AM

They are fun, as long as you don't have to sit on the platform. ;-)

9:34 AM

Bollywood + GTA

@Rubisco The heck is that ^ ?

An imgur link?

I SWEAR I DIDN'T DO ANYTHING

@Loong Oh, Bundeswehr?

@Rubisco XD

@AaronAbraham yes

Still serving?

( @Loong 's swag factor has just trebled )

Can someone help me out here?

0

Q: Why isn't the orbital angular momentum also considered while calculating the magnetic moments of electrons in period 4 transition elements?

My textbook ( Chapter: The d- and f- Block Elements ) makes an interesting assertion, however, without any reason to back it up. Now from what I've learnt from my physics classes last week, the magnetic moment of an electron is calculated using the formula: Where $m$ is the mass of the elec...

electrons transition-metals magnetism

9:43 AM

I love this pic. It never gets old

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Then there's this

Warning, it has one F-word

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10:05 AM

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10:38 AM

Do I have to be that guy again?

._.

@Kaumudi That's because it isn't complete bs.

6 hours ago, by John Rennie

@DHMO I don't think it's useful to use the term bullshit. It's just a level of approximation, and there are many levels of approximation.

user228700

@orthocresol Which guy?

user228700

@orthocresol Hm, yes, I got that...

Guy who rants in chat about how I don't like something.

Anyway, hybridisation is a perfectly valid model.

user228700

:-P What is it this time?

user228700

@orthocresol Yes, alright...I don't really care if it's perfectly valid or anything tho. I just wanna pass the stupid exam :-P

10:42 AM

Overly critical of hybridisation and other "high school" theories.

Anyway, SO3 is not sp2 hybridised.

If you think about it, S is forming six bonds, and there is no way the s and p orbitals (4 in total) can form 6 bonds

user228700

@orthocresol Yeah!

I believe that picture that you took is only trying to say that it is trigonal planar.

user228700

So it's an exception to the steric rule, yeah?

That is understandable, because of VSEPR, right?

user228700

Yes, it is.

10:44 AM

Does "steric rule" imply that trigonal planar => sp2?

If so, then yes, it is an exception.

user228700

@orthocresol Essentially.

Trigonal planar => sp2

Tetrahedral/trigonal pyramidal => sp3

Linear => sp

user228700

Yes, yes.

Something like that?

Great, I got you. :)

Did you figure out the azide ion?

user228700

Well, we determine something called the steric number and then using that number, we figure out the hybridization. Same principle, really.

10:45 AM

Yeah.

user228700

@orthocresol Yep :-)

$\ce{^{-}N=N^+=N-}$

user228700

Yep!

Great. Now, don't lose faith in hybridisation, everybody still uses it.

Even in university and beyond.

Unless you are a computational chemist, which this site seems to have a lot of.

user228700

Oh, yes OK, won't :-P I'm just finding it a bit hard, that's all. Omg, especially since apparently everything they taught me in high school isn't valid.

10:48 AM

A lot of it is simplifications.

But they are simplifications that, for the most part, work.

user228700

Hm...

And I really dislike the attitude that we sometimes see here, that whenever someone asks something about hybridisation, the first response is always something like "hybridisation doesn't exist" with the implication of "you are learning stupid things".

Or octet rule for that matter.

The truth is, even the smart compchem people deal with approximations and simplifications al the time.

And for the remainder of us, who are not compchem people, if you are in the lab, performing an experiment on methyl vinyl ketone, you don't want to go and run some long calculation to find out its geometry.

This is where the "useless" models of hybridisation come in.

user228700

@orthocresol Yeah, I get this a lot.

user228700

I understand what u're saying and I wouldn't know, 'cause I don't work in labs but I can imagine that it is frustrating.

Or if you are in an exam, and you are asked about how do BH3 and NH3 react.

:)

You can't whip out your laptop and write down "NH3 is $\mathrm{s^{1.045134859}p^{2.69849184}}$ hybridised."

It's great that humankind has the ability to calculate that now. However, simple models have their uses and they are here to stay.

user228700

10:59 AM

:-) I agree...

So, just with simple hybridisation, you can tell that BH3 is sp2 hybridised and has an empty p orbital, hence it is octet deficient and would love to accept another pair of electrons.

NH3 has a sp3 lone pair and gladly donates it to boron.

And that's exactly what happens. No need even for MO theory.

Now you can't explain everything with it, and that's why there are more sophisticated models, but it's really untrue to say that simple models are useless.

Ok. /ends rant

@orthocresol Except for BH3 not existing in a non-dimerised form ;)

@Jan I anticipated that... you...

1 min ago, by orthocresol

Now you can't explain everything with it, and that's why there are more sophisticated models, but it's really untrue to say that simple models are useless.

You're on my timed suspension list.

@orthocresol I only just came in, was going to answer Ringo xD

Along with @Rubisco

11:04 AM

@orthocresol Ooops, maybe I should retract my @orthomod vote …

:D evil laughter

I just hope main site doesn't see too much of these comments, or else I'm going to be grumpy on meta again..

> orthocresol be like

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Darth Wader.

user228700

@orthocresol: I have a quick question...are u busy?

Well... I am going to cook. But I will still be around here.

user228700

11:12 AM

Oh! What are u cooking? :-P

No idea... ._.

Probably some squid, crustaceans, molluscs, and a variety of fish

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9

@Hippalectryon ?

Rofl

user228700

Oh :-P Good luck, then. I was just gonna ask about why we include lone pairs in the hybridized orbitals...

@Loong I was trying to edit the seal's pic and got that weird result, just found it funny

11:14 AM

@Kaumudi It actually depends. So, for NH3, you'll hybridise everything.

user228700

@orthocresol Uh, OK..?

PH3, though, is better described by a 3s lone pair and P-H bonds using unhybridised 3p orbitals of P.

Hmm, I am not entirely sure how you can rationalise that.

user228700

Yeah, I've heard that example before...

Size of the central atoms. Non-hybridisation is preferred, but N can’t cope with three hydrogens at 90° angles.

Great :)

user228700

11:16 AM

@Jan Oh, right, OK...

user228700

Thank you :-)

user228700

And have fun cooking :-P

17 hours ago, by Rubisco

DHMO, the point is, it's fun showing off inaccuracies, but what you, I, and everyone else is studying is an approximation of reality, so after a certain degree, it becomes meaningless.

Oh, and I realized that sentence doesn't make much sense.

I got what you meant though.

@orthocresol That's the worst part

11:28 AM

Maybe I'm just reading it the way I want to :)

> for example, an experienced professional chemist who knows that he knows almost nothing about chemistry with only a limited exception, and a student who has just thoroughly studied a chapter of a book and now has the impression that he knows everything about this topic

The way I heard it was:

@orthocresol Here it comes . . .

When you're an undergrad you think you know everything. When you do a PhD, you realise you don't know anything. Then you become a professor and think that you know everything again.

@Loong Such words of wisdom that I can't confirm they are. Since you're my rival.

11:42 AM

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@Rubisco needs more coffee

@Loong *moar

12:00 PM

0

A: Why is absolute zero unattainable?

Wow, what a beautifully made up answer :D:D The usual answer is that it's unattainable because absolute vacuum is unattainable because the ground state of space-time itself has non-zero energy. This ground state occasionally condensing is what creates the virtual particles. Plus, apart from this...

Ideas about this answer?

Don't know enough to judge.

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4

12:16 PM

0

Q: Why do pregnant women turn toilet seats blue?

My partner is pregnant, and thought perhaps she was going mad when one day she found our toilet seat had turned blue. After some investigation, it seems this is a real phenomena, see here for a nice example, with the image from this link shown below. One explanation suggested is dye transfer f...

Not sure about the phenomenon, but I already retagged.

I’m inclined to call BS.

pH13 - Yet another Philipp

nice question ... wtf-chemistry

pentavalentcarbon

12:32 PM

@MelanieShebel that comment is bogus and don't believe it

Schtroumpf

pH13 - Yet another Philipp

@pentavalentcarbon approved

12:48 PM

@orthocresol do nucleophiles attack the oxygen atom in phenol?

@pH13-YetanotherPhilipp Are you building LCAO of 4d orbitals?

pH13 - Yet another Philipp

@DHMO could you be more precise, please?

user228700

Hey, is oxygen capable of forming 4 bonds and expanding its octet?

@Kaumudi 4 bonds, theoretically yes but nobody observed it yet; expanding octet, no.

user228700

Alright...

In water oxygen can make four bonds

user228700

12:52 PM

But how the heck can I ascertain if an atom is capable of expanding its octet or not?! 😐

It depends which kind of bond you're speaking

Two covalents and two H-bond

7 hours ago, by pH13 - Yet another Philipp

@DHMO but then the resulting MOs are more interesting, than the pure AOs

@pH13-YetanotherPhilipp here, click

@9-BBN has this been confirmed?

@Kaumudi a molecules does not expand octet; an atom does

no atoms below period 3 can expand octet

@pH13-YetanotherPhilipp I don't know what you meant by this:

user228700

Uhh, sorry, typo.

7 hours ago, by pH13 - Yet another Philipp

I am repeating another calculation j4f

In theory this is possible

12:54 PM

2 mins ago, by DHMO

@Kaumudi 4 bonds, theoretically yes but nobody observed it yet; expanding octet, no.

pH13 - Yet another Philipp

@DHMO I’m redoing a calculation from a paper about Mo2

user228700

@DHMO What?! What about the d-block elements?!

@pH13-YetanotherPhilipp I see

@Kaumudi they do expand octets.

@pH13-YetanotherPhilipp do nucleophiles attack phenol?

pH13 - Yet another Philipp

@DHMO I seldom answer such questions - also in chat - without your own input, as this is a homework question. ;)

@pH13-YetanotherPhilipp alright. From the resonance of phenol (see below), I notice a positive charge on the oxygen. My question is, then, do nucleophiles (like hydrogen ion) attack the phenol's oxygen atom?

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pH13 - Yet another Philipp

1:00 PM

so you are asking, if H+ attacks O+ ?

@pH13-YetanotherPhilipp oh, hydrogen ion is not a nucleophile

I suddenly have no examples of nucleophiles

@pH13-YetanotherPhilipp -:OH should be a nucleophile

but does anything attack the oxygen atom there at all?

And do what for example?

@9-BBN ??

If you have this idea maybe you thought about something

well I saw the positive charge on oxygen

yes, I just thought about something

that the positive charge is a formal charge which means nothing

1:10 PM

Look at that oxygen, does it have a vacant orbital to be attacked?

@orthocresol I don't think so

Octet rule.

@orthocresol yes?

1:46 PM

Has anyone here done a self-question?

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I thought the z2 are closer when it is 2 short 4 long? Why are their energies higher?

2:10 PM

Whoever voted to close this as a medicine question, please provide your reasoning. As far as I know, toilet seats won’t visit doctors (and aren’t concerned about their health). — Jan 11 secs ago

@ringo NotWoodward notes, that a lithium ester enolat’s geometry is different from one of a magnesium ester enolate, and also answers the third and fourth questions. I’m missing answers to the following:

@Jan Well, in my defense, it wasn't me.

Pointing a finger at candidate Loong, so he destroys his reputation

1. Can I define the geometry without knowing an attached atom?
2. What’s the deal if there could be two attached cations with different priorities (e.g. lithium or sodium)?

@Rubisco Pointing at people, are we? It’s rude to point a naked finger at a dressed colour plate thingy! Even if it’s a zinc finger!

(Not sure if RuBisCO has a zinc finger, though xD)

@Jan My fingers are made of phenylalanine

@Jan Pot calling the kettle black?

2:34 PM

@Rubisco Could you help me?

1 hour later…

3:40 PM

sigh

@Loong , please see again. That wasn't my doubt .I didn't know from where to start counting .Remove that Duplicate box. — Tilak Madichetti 12 mins ago

So you want me to make an exact copy of my answer and just replace “hept-1-en-6-yne” with “pent-1-en-4-yne”?

@Loong I'm glad to see that the 2013 version hasn't changed much.

@Loong Should I just pick a random rule from the book and then make a self-question?

@DHMO Yes, the wording of this rule has been changed, but the resulting names are the same.

@DHMO I am not sure whether a random rule would be interesting for the community.

Numbers as low as possible are given to double and triple bonds as a set, even though this may at times give "-yne" a lower number than "-ene".
Locants as low as possible are given to multiple bonds as a set, even though this may at times give ‘yne’ endings lower locants than ‘ene’ endings.

So they were not called locants in 1993?

And... quadruple bonds?

They elaborated on this (below 1993):

The presence of both double and triple bonds is similarly denoted by endings such as "-enyne", "-adienyne", "-enediyne", etc.

Only the lower locant for a multiple bond is cited except when the numerical difference between the two locants is greater than one, in which case the higher-numbered locant is cited in parentheses (see R-0.1.4).
Only the lower locant for a multiple bond is cited, except when the numerical difference between the two locants is greater than one, in which case the higher locant is enclosed in parentheses.

higher-numbered locant > higher locant ??

What exactly is a locant?

@DHMO the 1993 recommendations had locants, too: acdlabs.com/iupac/nomenclature/93/r93_42.htm

4:14 PM

wolframalpha.com/input/?i=nitrogen+400+%C2%B0C+220+bar — Loong 58 mins ago

High-technology Google ^^

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@orthocresol I usually use NIST REFPROP for steam tables and similar calculations in my answers; however, that doesn't help other users. That's how I found the data on WolframAlpha.

But I am not sure how far I can trust that site.

4:49 PM

4

Q: Competitive 'Wittig' vs 'Peterson' C=C bond formation

If one considers the intermediate above, there are immediately two possibilities for subsequent reaction: 1. A Wittig-type olefination which would lead to a vinyl silane: This reaction happens to be unproductive as the vinyl silane can't do any further chemistry under the reaction conditions ...

organic-chemistry

1 hour later…

6:10 PM

when we write that "suspension was aliquoted to 5 ml tubes", is it simply synonymous with "suspension was poured into 5 ml tubes"?

@CowperKettle yes, with the implied intention that all tubes contain idential solutions

0

Q: How can I make changes in my profile?

I have been here for 3 months and after seeing that everybody has a unique name and picture here I have decided to change mine too, but I don't know how to do it. Please help. Thanks.

support profile-page

@Loong Thank you, Loong! Good evening!

hi

@1,3-feeds looks like that's already done

1 hour later…

7:31 PM

heh, seriously though, i've gotta go

bye

@orthocresol bye

Thank God. For a moment there I thought . . .

Since I've been in this situation before.

And I'd make a good mod, since I've been in situations before.

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Transcript for

Oct '1615

The Periodic Table

Haikus are awesome / Chemistry's even better / So pull up a chair

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