Dipole Moments

[Kassandra Molina 2B]

How can you determine which element will affect dipole moments? Or is it depending on the compound? In other words, is determining dipole moments dependent on what the element is in a compound or the structure of a compound? I'm having a hard time grasping dipole moments.

[Rita Dang 3D]

I think dipole moments depend on the electronegativity of each element and also the structure of the compound. By looking at the structure of a compound and determining its shape, we can decide whether the dipole moments cancel each other or not. In other words, we need to know the lewis structure and molecular shape before we determine dipole moments.

[Austin Ho 1E]

What Rita said is correct. The difference in electronegativities are more important than the values of electronegativity themselves. Also, you need to understand molecular shape to understand dipole moments: look at how 'balanced' the differences in electronegativity are. For example, in CCl4, the tetrahedral shape means that all the dipole moments of the C-Cl bonds cancel. However, if you add a H instead of a Cl, you get CHCl3, and the dipole moments no longer cancel.

Look at the difference in electronegativites rather than individual atoms.