A molecule has sp3 hybridization with 1 lone pair. The electron pair geometry of this molecule is: . The geometry of this molecule is: This molecule will have approximate bond angles of (If more than one bond angle is possible, separate each with a space.):

Tetrahedral

Trigonal pyramidal

less than 109.5°

Explanation:

If a molecule has a hybridization of sp3 it must have four electron domains which corresponds to a tetrahedral geometry.

Now we were told that the molecule also has one lone pair. It means that one out of the four electron domains is composed of a lone pair. Thus the molecular geometry will be trigonal pyramidal (e.g NH3).

Recall that lone pairs usually decrease the bond angle to a value less than the expected value for that particular electron domain geometry.

The expected bond angle for a tetrahedral geometry is 109.5° but that of the trigonal planar geometry is less than this.