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    • C 3 – rotation by 120 o
    • C 4 – rotation by 90 o
    • C (infinity rotation axis) – rotation of any amount will result in an indistinguishable orientation
  • Does the molecule have an inversion center (i) ?

Determine which of these symmetry elements are present in your assigned molecules. All of the columns of the table on the report form should be filled out. If you have any difficulty determining whether such symmetry elements are present in the molecules you are assigned, your TA can provide examples of each symmetry element.

Extra credit points can be earned by indicating in the table how many of each symmetry element are present for each molecule (i.e. How many mirror planes are present?).

  2. Mirror Images

Using the model kits, build models which are the mirror images of the models you were assigned to build (b, c, d, e, f, g, h, i and j) in Part 1. With the two mirror images in hand, try to place the models on top of one another, atom for atom.

If you can do this, the model and its mirror image are superimposable mirror images of one another. If not, the molecule and its mirror image form nonsuperimposable mirror images. Nonsuperimposable mirror images are also known as enantiomers .

For each compound, decide whether the mirror image is superimposable or nonsuperimposable. Can you make a generalization about when to expect molecules to have nonsuperimposable mirror images?

  3. Isomers

In this exercise you will build models of compounds which are structural and/or geometrical isomers of one another.

Make the following models:

A. Structural Isomers

  1. Make a model(s) of C 2 H 5 Cl. How many different structural isomers are possible?
  2. Make a model(s) of C 3 H 7 Cl. How many different structural isomers are possible?
  3. Make a model(s) of C 3 H 6 Cl 2 . How many different structural isomers are possible?

 B. Geometrical Isomers

  1. Make a model(s) of C 2 H 3 Cl. How many different structural and geometrical isomers are possible?
  2. Make a model(s) of C 2 H 2 Cl 2 . How many different structural and geometrical isomers are possible?
  3. Make a model(s) of cyclobutane (C 4 H 8 ). HINT : cyclo = ring of C atoms
  4. Now make dichlorocyclobutane (C 4 H 6 Cl 2 ) by replacing two H atoms on cyclopropane with Cl atoms. How many different structural and geometrical isomers are possible for dichlorocyclobutane? You may wish to make a couple of cyclobutane molecules so that you can compare the structures. Do any of the isomers have nonsuperimposable mirror images?

C. Aromatic Ring Compounds

  1. Make a model of benzene, C 6 H 6 . Even though your model will contain alternating double and single bonds, remember that in the real molecules of benzene all the C-C bonds are equivalent. What symmetry elements does benzene possess?
  2. Make a model(s) of chlorobenzene, C 6 H 5 Cl. How many different structural and geometrical isomers are possible?
  3. Make a model(s) of dichlorobenzene, C 6 H 4 Cl 2 . How many different structural and geometrical isomers are possible?
  4. Make a model(s) of trichlorobenzene, C 6 H 3 Cl 3 . How many different structural and geometrical isomers are possible?

4. Hypervalent Structures

Hypervalent compounds are those that have more than an octet of electrons around them. Such compounds are formed commonly with the heavier main group elements such as Si, Ge, Sn, Pb, P, As, Sb, Bi, S, Se, Te, etc. but rarely with C, N or O. Refer to the rules for Electron Domain theory in order to assign Lewis structures to the following molecules. Describe possible isomeric forms and the bond angles between the atoms. How many lone pairs of electrons are present on the central atom of each molecule, if any? (** Your book will be very useful in aiding you with these structures **)

  1. PF 5
  2. PF 3 Cl 2
  3. SF 4
  4. XeF 2
  5. BrF 3

Questions & Answers

what is Nano technology ?
Bob Reply
write examples of Nano molecule?
The nanotechnology is as new science, to scale nanometric
nanotechnology is the study, desing, synthesis, manipulation and application of materials and functional systems through control of matter at nanoscale
Is there any normative that regulates the use of silver nanoparticles?
Damian Reply
what king of growth are you checking .?
What fields keep nano created devices from performing or assimulating ? Magnetic fields ? Are do they assimilate ?
Stoney Reply
why we need to study biomolecules, molecular biology in nanotechnology?
Adin Reply
yes I'm doing my masters in nanotechnology, we are being studying all these domains as well..
what school?
biomolecules are e building blocks of every organics and inorganic materials.
anyone know any internet site where one can find nanotechnology papers?
Damian Reply
sciencedirect big data base
Introduction about quantum dots in nanotechnology
Praveena Reply
what does nano mean?
Anassong Reply
nano basically means 10^(-9). nanometer is a unit to measure length.
do you think it's worthwhile in the long term to study the effects and possibilities of nanotechnology on viral treatment?
Damian Reply
absolutely yes
how to know photocatalytic properties of tio2 nanoparticles...what to do now
Akash Reply
it is a goid question and i want to know the answer as well
characteristics of micro business
for teaching engĺish at school how nano technology help us
Do somebody tell me a best nano engineering book for beginners?
s. Reply
there is no specific books for beginners but there is book called principle of nanotechnology
what is fullerene does it is used to make bukky balls
Devang Reply
are you nano engineer ?
fullerene is a bucky ball aka Carbon 60 molecule. It was name by the architect Fuller. He design the geodesic dome. it resembles a soccer ball.
what is the actual application of fullerenes nowadays?
That is a great question Damian. best way to answer that question is to Google it. there are hundreds of applications for buck minister fullerenes, from medical to aerospace. you can also find plenty of research papers that will give you great detail on the potential applications of fullerenes.
what is the Synthesis, properties,and applications of carbon nano chemistry
Abhijith Reply
Mostly, they use nano carbon for electronics and for materials to be strengthened.
is Bucky paper clear?
carbon nanotubes has various application in fuel cells membrane, current research on cancer drug,and in electronics MEMS and NEMS etc
so some one know about replacing silicon atom with phosphorous in semiconductors device?
s. Reply
Yeah, it is a pain to say the least. You basically have to heat the substarte up to around 1000 degrees celcius then pass phosphene gas over top of it, which is explosive and toxic by the way, under very low pressure.
Do you know which machine is used to that process?
how to fabricate graphene ink ?
for screen printed electrodes ?
What is lattice structure?
s. Reply
of graphene you mean?
or in general
in general
Graphene has a hexagonal structure
On having this app for quite a bit time, Haven't realised there's a chat room in it.
how did you get the value of 2000N.What calculations are needed to arrive at it
Smarajit Reply
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Source:  OpenStax, Honors chemistry lab fall. OpenStax CNX. Nov 15, 2007 Download for free at http://cnx.org/content/col10456/1.16
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