Hybridization Lecture Confusion

[Jenny Chau 1I]

On lecture 23 (I think), Professor Lavelle started out the lecture with an example of NH3 and wrote out the electron configuration of N. According to my notes, he then mentioned that when you draw out the electron configuration you'll notice that it won't give you the correct shape because the overlapping H and N orbitals will make 90 degree bond angles and thus you'll want to invoke hybridization. I'm wondering how did he derive that the bond angles will be 90 degrees from looking at the electron configuration? I'm sorry if what I have written is confusing because this is all based on what I have written in my notes.

[Bailey Giovanoli 1L]

I'm not so sure that he was looking at the electron configuration. I think he was using his knowledge on VSEPR shapes, and how they couldn't be in the same plane because whenever he talks about 90-degree bonding angles not being desired he seems to be talking about VSEPR and how it allows for the use of three planes instead of one that you see when doing a lewis structure.

[Adalia 3E]

I think he brought up the 90 degree example to demonstrate how just looking at atomic orbitals will not bring the right shape, so you'd need to invoke hybridization to create the 4 hybrid orbitals and find the accurate ~109.5 degree angles