The structure of amines

The nitrogen atom of amines is surrounded by 3 covalent bonds and one free electron pair. Amines have →   therefore a tetrahedral structure. When $R_1$, $R_2$ and $R_2$ are different, one may wonder if the amine is not chiral..

Click on the image !

It is not so because the (much faster than shown) reverse movement does not allow chirality !