[proteekrosul]

In Phosphorus trichloride (PCl₃), the central phosphorus atom has 3 bond pairs of electrons and 1 non-bonding pair of electrons. The 3 Chlorine atoms have 3 non-bonding pairs of electrons each. So does that mean the compound PCl₃ has 1+3*3 = 10 lone pairs of electrons in total, or do we just count the lone pairs of the central atom (Phosphorus in this case)?

[chenbeier]

You count die lone pair of the atom you looking for. P has 1, each  chlorine has 3. To react with more chlorine or oxygen die lone pair of phosphorous is important.