<p>WHat's your major?
Which prereqs have u done?</p>
<p>Not a chem major but since some of you are can you help me with this: How can you tell when something has a "dipole moment", why is HF the most electronegative compund? I need to pass this class and I'm not that confidant with the final coming up next week.</p>
<p>To know if something has a dipole moment u need to c if molecule IS polar. Polarity occurs when one element is very electronegative, such as Flourine, which is the most electronegative element. This type of situation is also described as imbalance if charges. Elements around F are also very electronegative.</p>
<p>To tell if u have a polar molecule, u got to draw the lewis structure. You have to consider shape of the molecule. A linear molecule CO2 is not polar and has no dipole moment.</p>
<p>NOw look at water, it's a bent molecule, therefore it does have a dipole moment. The e- are attracted to Oxygen from both sides.</p>
<p>As for HF. U know that F is the most electronegative element, H is very weak. It has one proton, so it will give up the e- very easily, while F will take the e- very easily. Big difference between them. </p>
<p>There also also tables of electronegativity to help c if a molecule will turn out to be ionic, covelent, polar etc. ONly covelent bonds can be polar.</p>
<p>To sum it up and put it in non scientific terms.
1. Electronegativity: One strong element able to steal e- (F) -1 chrage, one weak element H, +1 charge willing to give up E-</p>
<ol>
<li>Dipole moment- big difference in electronegativity, electrons pulled in one direction to one element, like to O in H2O.</li>
</ol>
<p>I could also talk about orbital diagrams and and electron density. I dunno how specific u wanna get</p>
<p>Another thing is u can have polar bongs, like CO2, but it won't be a polar molecule and have no dipole moment. It's linear, 180% u have something like this.</p>
<p>pulling to left O=C=O pulling to the right. Therefore, the two polar bounds cancel each other and u have no dipole moment</p>
<p>bump please, re: admission not polarity :)</p>