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Ethan Tsai
1 N. College Street
Northfield, MN 55057

TSAIE@Gridley.ACNS.Carleton.edu
http://public.carleton.edu/~tsaie/ethan.html

Quote of the day:
"Why are we surprised when politicians play politics? It's not like they
are supposed to be real adults... they are, after all, politicians and
don't have real jobs and aren't playing around with their money." 
     --Max 

On Thu, 12 Feb 1998, Happosai wrote:

The following is part of a scene which I'm planning to put into Aikan Muyo 
Chapter#11. It builds on Washuu's "love is chemistry, sex is physics, 
kinkyness is engineering" comment in Chapter#8. It's been quite a few 
years since I took chem class, so I'd appreciate it it someone who's more 
competent in the subject would take a look at this and tell me if I'm 
having Washuu commit any significant scientific errors in her metaphor. I 
do *not* want to make the universe's greatest genius sound like an idiot.

...

Suddenly, chairs and desks appeared out the lab floor directly underneath
Tenchi, Ryoko, and Aeka, forcing them to take a seat or be knocked aside.
They sat. Washuu walked in front of them, dressed in a professor's robes,
and tapped a podium that had appeared in the same manner as the desks.

"We will begin by studying the relationship which you three are in, a
grouping which chemists call a 'covalent bond,'" began Washuu.

Ryoko smirked. "Aeka's the one who's into bondage, not *me*."

Nice pun!

A large ceramic cat statue landed on Ryoko's head with a loud "clang!"

"Owwwww!"

"Raise your hand for permission to speak," admonished Washuu. "As I was
saying, a covalent bond is when two atoms are held together by sharing 
electrons."

Covalent bonds are known to exist with more than a pair.  It can number
up to six electrons, but there are a lot of technicalities.

a lot of bonds also are characterized as being covalent in character.  A
technical point, but one you might want to consider.  Pure covalent bonds,
on the other hand, can range from one to six.  Again, that's in the purest
sense of a covalent bond.  I'm probably confusing you, but I can explain
better in detail in another message if you want.

Aeka raised her hand.

"Yes, Aeka-san?" said Washuu, nodding.

"Do you mean, when one atom shares an electron which belongs to it with
another atom which doesn't have one?"

"No..." replied Washuu.

A large salt shaker landed on Aeka's head.

"Owwww...!"

"...that's *ionic* bonding. The subject of the class today is *covalent*
bonding." 

Actually, it's still covalent.  Technically, ionic bonds are interactions
of charges that exist in regards to the molecule as a whole.  Sodium
chloride doesn't really "share" an electron as it does maintain attraction
through the interaction of the positive and negative forces that exist
around the atoms.  Also you'ce just described metallic ionic/covalent
bonding there, more specifically than ionic....  Again, I can explain in
detail on request.

A large viewscreen appeared behind her, showing two atoms with 
swarming electron clouds around them. Strangely enough, the nuclei looked a
lot like Ryoko and Aeka's faces. In addition, one of the electrons looked
like Tenchi. It looped alternately around the Aeka nucleus, then the Ryoko
nucleus, back and forth. Washuu cleared her throat, then raised her pointer
and tapped the Tenchi electron. 

Technically, the Tenchi electron won't loop.  In fact, if anything, it
should be wavering in between (not standing still mind you).  It's a
better representation than lopping back and forth.  If it were looping
back and forth, you'd be illustrating something closer to two subatomic
particles with an electron orbiting it.  Covalent bonds indicate "sharing"
and also a much higher probability of finding the electron somehwere
between the two nuclei.  Note that it doesn't necessarily mean that it's
exactly halfway between the nuclei!

"Quantum theory tells us that a valence electron in a covalent bond 
will interact with both nuclei equally, and the overlap of the atoms'
orbitals makes it impossible to determine which atom the electron belongs
to. In fact, it would be more accurate to say that the electron belongs to
*both* atoms. Understand this so far?"

Actually, equal interaction with both nuclei will only occur if the
molecule is a homogenous diatomic molecule.  No covalent bond is ever seen
as equal if it involves to atoms that are not the same.  Electron affinity
and electronegativity will dictate a "preference" of the electron to stay
around one nucleus versus another.

Tenchi, Aeka, and Ryoko nodded.

"The formation of a covalent bond is often a violent event, involving the
release of large amounts of energy." The screen filled with an image of 
the Hindenberg crashing to the ground in flames. "Here we see the formation
of bonds between hydrogen and oxygen atoms."

Yes, but that's a classic case.  A good number of covalent bonds form
without exothermic reactions.  I would say that most aren't violent
either.  It's the formation of most oxides, or redox reactions that result
in covalent bonds that are violent.  Also violent reactions are indicative
of violent reagents, not of a particular bond forming.

"Ouch," winced Tenchi, under his breath.

"Once the bond is formed, the atoms become a stable molecule, and they
strongly resist being broken apart..."

Not really.  Covalent bonds are actually fairly easy to break, depending
on the molecule.  On the other hand, they are notoriously stable...

Ryoko and Aeka glanced at each other, their expressions very skeptical.

"...but a covalent bond will not form between atoms which just share *one* 
electron."

Actually, they can.  They're just not necessairly stable.  On the other
hand, there are some metalloorganics that are considered covalent bonds
that actually only formally share an odd pair of electrons due to the
bonding properties/order of the metal.

Aeka, Tenchi, and Ryoko blinked, looked at each other, then glared at
Washuu. "NO WAY!!!" they shouted simultaneously.

Washuu rapped each of them over the knuckles with her pointer. "Raise your
hands before speaking!" she reminded them.

Then she sighed and took off her cap, placing it on the podium. She 
walked behind Ryoko and Aeka and put her hands on their shoulders. "All I'm
saying is that you two need to have something in common besides Tenchi,"
Washuu said gently. "Understand?"

I'll agree with that last statement!

Hassheen!

Sorry if I sounded crass, rude, or condescending.  I apologize if you've
taken umbrage at the comments.  I'd like to point out that I think this is
one of the best Tenchi fanfic series out there, and I'm a big fan.  On the
other hand, I'm also a devout organic chemist.  

If you need any more help getting down Washuu's technobabble, feel free to
email me.  I'll try to help any way I can!

Ja ne!