The Lewis dot structure for P, the chemical symbol for a single atom of phosphorous, is written with a P surrounded by two dots together on one side and three single dots on the three remaining sides. Each dot represents a valence electron.
The two electrons that are represented by two dots next to one another are the two electrons in the 3s shell. The 3s shell contains a maximum of two electrons. The remaining three dots, which are not represented in pairs, are the three electrons in the half-filled 3p shell. The number 3 represents the energy level of the valence electrons.