Lecture VSEPR

[Carolina Lechuga]

Hey, so on November 15, Lavelle said in his lecture that "VSEPR models can predict distortions qualitatively but not quantitatively" what exactly does this mean ? I have class during his office hours so if anyone can explain that would be great!

[ryanhon2H]

I think what it means is that VSEPR models can tell you the general shape of the molecule, such as bent, tetrahedral, square planar, etc, so that would be qualitative.

Quantitative I think is the the angles of the bonds, so while VSEPR models can predict the general molecular geometry, it can't predict the exact bond angle, due to different repulsions from different molecules or lone pairs.

[Bruce Chen 2H]

We can easily measure the qualitative properties of a structure as the shape or polarity. However, exact bond angles can't be measured directly, which is what I think he means by we can't measure it quantitatively.