Answer:
atom are very tiny partical
It is covalent bonding. The electrons are shared between the phosphorus and the chlorines.
covalent bonding is when electrons are shared between two elements.
molecular polarity is a little bit complicated, but I will try to explain ;)
PCl3 is an alternation on tetrahedral molecules.
It means that P has one lone pair of electrons. This pair of electrons are only attracted to the P nuclei and thus a greater freedom of motion.
This means that their orbital is bigger and this pushes the 3 Cl atoms closer together.
The angle between each Cl now is 107 and the angle between Cls and P is greater than 107.
Now, due to this shape, and also electronegativity (Cl is more electronegative than P meaning that it tends to hog the electrons they share closer to itself), PCl3 is polar. Electrons that are shared tend to flow closer towards the Cl than the P side.
Therefore, on the Cl side of the molecule it's, more negative. On the P side, it's more positive.
