Ammonia has three bonds and one lone pair around its nitrogen atom. What is the shape of the molecule?

1. Four regions of electron density around nitrogen spread into a tetrahedral arrangement. 2. Molecular shape names only the positions of the atoms, not the lone pair. 3. Removing the lone pair from the tetrahedral picture leaves three hydrogen atoms below the nitrogen. 4. That arrangement is a trigonal pyramid, with nitrogen at the apex. 5. Calling it a flat triangle would mean ignoring the lone pair and pushing all four atoms into one plane. _Source: OpenStax Chemistry (CC BY 4.0), Chs 7 and 17, section 7.6 Molecular Structure and Polarity_