Phosphorus trichloride, PCl₃ is a liquid at room temperature.

Explain this observation in terms of the particles, structure and bonding of PCl₃.

Phosphorus trichloride, PCl₃ undergoes change in bonding and molecular force of attraction, causing it to be liquid at room temperature.

Explanation:

Unlike other chlorides of Period 3 elements, Phosphorus trichloride, PCl₃ changes the structure of its molecular bonding from ionic to covalent bonds as it transitions to fluids (liquids or gases). The PCl₃ molecule also has the weak Van der Waals dispersion and dipole-dipole attraction, making it a fuming liquid at room temperature, with no electrical conductivity.