Please Help?

Question

I have a huge end of semester test and i need help understanding hybridization and answering some of these questions. anything helps...thanks.


1.SO2-
Why doesn't his create a double bond?

2.How do you know polarities based on the shape of a molecule or bond?

3.NO2-
Why is this hybridized as sp2 shouldn't it be sp since it has two unpaired electrons

4. NH3
why is this hybridized as sp3 shouldn't it be sp since it has 2 unpaired electrons

5. how do you draw out hybridizations

6. what factor determines the shape of a molecule

7. Can a molecule be polar w/o polar bonds w/ in the molecule

8. Can a molecule with polar bonds be nonpolar

9. How do you know whether a molecule or bond is paramagnetic or diamagnetic

Answer 1

First off, I don't do people's homework, so I'm going to try and "lead" you in the right thinking direction rather than just hand you the answer. My suggestions follow, using the number of your questions above as reference.

1. Re-read your sulfur chemistry

2. Two words: electron density. Two more words: Dipole moment

3. There's an electron (lone) pair that you've forgotten to account for...

4. See #3. Extra electron pair on the N

5. Should be easily reproducible diagrams in your text. Open it.

6. Several. Start with my answer to #2.

7. Yes, if it contains an induced dipole.

8. Absolutely. Example: Carbon tetrachloride

9. Determine the electron configuration and then address the
definition of "paramagnetic" or "diamagnetic"...

Answer 2

Many of your questions can be answered by making sure you have the correct Lewis dot structure. Once that is done count the "regions of high electron density" where a bond counts as one region (double bonds count as one region, so do triple bonds) and unpaired electrons count as one region.

q. 2 I'm not sure what you are asking. The polarity of a MOLECULE depends on the shape of the molecule. Symmetrical molecules are usually non-polar (polarities cancel). BONDS are polar if the atoms attached to either "end" have different electronegativities. (There should be a list or chart of electronegativities in your text).

q. 3 Make sure you have the correct Lewis dot structure; there is an odd unshared electron.

q. 4 Remember to count each bond AND each unshared pair of electrons as regions of high electron density.

q. 5 - see your text; there should be drawings there

q. 6 Molecular shape is determined by electronic geometry (regions of high electron density) AND by the presence of unshared electrons. Unshared electrons "distort" the shape.

q. 7 Yes - induced dipoles

q. 8 Symmetrical molecules (tetrahedron, planar triangle, linear diatomic) tend to be non-polar if all bonds are to the same element.

q. 9 paramagnetic elements have unshared electrons; diamagnetic elements have no unshared electrons. Write the electron configurations.