What is the structure of nitrite?
Nitrogen is actually surrounded by 3 effective pairs. But 2 of them are bonding and the third one is a lone pair. According to VSEPR theory, the structure should be  trigonal planar.


The angle is not exactly $120^\circ$, as the electrostatic  repulsion between non-bonding pair and bonding pair is higher than the repulsion between two bonding pair. So, the angle of $\ce{O-N-O}$ is slightly smaller than $120^\circ$.
The distribution of the three electron effective pairs is trigonal planar. But the molecule structure is bent (like letter V).