Bond Angles

[Christina Diep 3A]

How do we know whether a bond angle is 104.5 degrees instead of 109.5 degrees like H2O?

[Jonathon Jauregui]

The Bong angle that becomes 104.5 is when there is an electron density region that is lone pairs that push the bond angles closer together. Since Ion-ion has the most repulsion in the molecule meaning that the bond angle will be less than if they were all boned to an atom.

[Donovan McGraw 2C]

Because lone pairs take up more space than single bonds, the single bonds in H2O are pushed closer together giving off a bond angle smaller than 109.5. The bond angle for 4 groups is typically 109.5, but this differs in water because of the two lone pairs.

[Jasmin Gonzalez]

In order to determine bond angles we can look at the arraignment of the atoms and the number of electron pairs around the central atom. For H2o the bond is known to be v-shape and 104.5 and can be determined with molecular geometry and repulsion between electron pairs. But in general, we can determine bond angles through the theoretical model and VSEPR theory.

[CristinaG]

The bond angle of water is 104.5 degrees because 2 of its 4 electron dense regions are lone pairs. The lone pairs have a stronger repulsion than sigma bonds and therefore have a stronger push on the other bonds. A tetrahedral with no lone pairs in its electron dense regions would have the bond angle of 109.5.