Final answer:
The central atom in phosphorus trifluoride (PF3) is phosphorus, symbolized as P. Phosphorus binds with three fluorine atoms to form PF3, fulfilling the octet rule with eight valence electrons around the central atom.
Step-by-step explanation:
In the molecule phosphorus trifluoride (PF3), the central atom is phosphorus, which is denoted using the chemical symbol P. Phosphorus is a common central atom in many compounds due to its ability to form multiple bonds with other atoms. It has five valence electrons, which allows it to bond with three fluorine atoms, each contributing one electron to form three single bonds. This results in a total of eight valence electrons around the central phosphorus atom, fulfilling the octet rule for phosphorus in this molecule.
Other compounds where phosphorus serves as the central atom, like phosphorus pentachloride (PCl5) and phosphorus pentachloride, involve phosphorus undergoing sp3d hybridization to accommodate more than eight valence electrons - an example of an expanded octet. However, this is not the case with PF3, where the standard octet is observed. Phosphorus trifluoride is an example of a simple covalent molecule where a single phosphorus atom bonds to three fluorine atoms, each with seven valence electrons.