Need help with the VSEPR Model

Test Preparation
1

<p>Can someone please explain how the VSEPR Model work? I really do not get it and my final is coming up very soon.</p>

2

<p>Valence Shell Electron Pair Repulsion</p>

<p>This is where you have some elements bonded together.</p>

<p>First take the most unique element (the one with the least electrognegativity) and put it in the center.
If carbon is an element, put it in the center.</p>

<p>Then put all the other elements around the center one and draw one bond between all the elements to the center.</p>

<p>Count out how many electrons are left, if you can make all the elements stable with the remaining electrons, add them around the elements, otherwise make another bond between the center atom and an element.
Repeat the process.</p>

<p>Once all elements are stable, the remaining electrons (if there are any left) go around the center atom. </p>

<p>Hope that helps</p>

3

<p>but I don't get how the number of pair electrons and lone pairs can predict the shape of the molecule?</p>

4

<p>Once you draw the model out, you will be able to determine the shape by looking at it.</p>

<p>Remember that if the center atom has electrons around it, it forces the other elements to repel each other; therefore, forming a different shape than what was drawn.
The elements will be bent at angles.</p>

<p>Try searching it on google if your book doesn't help.
Try this site too: <a href="http://chemviz.ncsa.uiuc.edu/content/lab-s-shapes.html%5B/url%5D"&gt;http://chemviz.ncsa.uiuc.edu/content/lab-s-shapes.html&lt;/a&gt;&lt;/p>

5

<p>Basically, VSEPR theory takes into account the fact that all electrons repel each other (due to electron-electron repulsion) so when pairs of them congregate themselves around in a molecule, they repel each other so they can be as far as possible from each other. VSEPR theory uses this to calculate the shapes that come from this.</p>

<p>Even if a pair of electrons is unbonded, it still repels those that are bonded, which explains why H20 is bent instead of linear, even though it only has 2 bonded pairs of electrons (but the other 2 nonbonding pairs on oxygen still repel each other).</p>

<p>Hope this helps</p>

6

<p>Vastly
Stupid
Erroneous
Piece of
Rat ****</p>

<p>Biology rules.</p>

7

<p>lol Biology and Chemistry, I think go hand in hand.</p>

<p>As for the science that rules.</p>

<p>Physics Rules!!!</p>