Question

Use Lewissymbols and Lewis structures to diagram the formation of \(\mathrm{PF}_{3}\) from \(\mathrm{P}\) and \(\mathrm{F}\) atoms.

Short answer

To show the formation of \(\mathrm{PF}_{3}\) using Lewis symbols and structures, first determine the valence electrons for \(\mathrm{P}\) and \(\mathrm{F}\) atoms: P has 5 valence electrons and F has 7. Next, draw their Lewis symbols: P: \\[ \cdot P ^{\circ}\cdot \\] F: \\[-] F ^{\bullet\circ} \\] Combine one P atom and three F atoms to form \(\mathrm{PF}_{3}\) by sharing two electrons between each P and F, making single covalent bonds. The final Lewis structure for \(\mathrm{PF}_{3}\) is: \\[ \mathrm{F} : \overset{\circ}{\mathrm{F}} \mathrm{P} - \mathrm{F} : \\] This shows that \(\mathrm{PF}_{3}\) has three single covalent bonds between the central P atom and each of the three F atoms, with three lone pairs on each F atom.

Step-by-step solution

Determine the valence electrons for P and F atoms

To draw the Lewis symbols and structures, we need to know the number of valence electrons for each element. Phosphorus is in group 15 and has 5 valence electrons, while Fluorine is in group 17 and has 7 valence electrons.

Draw Lewis symbols for P and F atoms

Using the number of valence electrons, we can draw the Lewis symbols for both phosphorus and fluorine. The phosphorus atom is represented by the symbol 'P' surrounded by 5 dots representing the 5 valence electrons. The fluorine atom is represented by the symbol 'F' surrounded by 7 dots representing the 7 valence electrons. P: \\[ \cdot P ^{\circ}\cdot \\] F: \\[-] F ^{\bullet\circ} \\]

Combine P and F atoms to form PF3

To form \(\mathrm{PF}_{3}\), one phosphorus atom bonds with three fluorine atoms. Each bond between the P and F atoms is formed by sharing two electrons, one from P and one from F. This forms a single covalent bond. The Lewis structure of \(\mathrm{PF}_{3}\) will have P as the central atom, surrounded by three F atoms, connected by single covalent bonds.

Complete the Lewis structure for PF3

To show the Lewis structure for \(\mathrm{PF}_{3}\), we need to indicate the shared and unshared electrons in the molecule. The shared electrons between the P and F atoms form the single covalent bonds, and the unshared electrons remain with the F atoms as lone pairs. The final Lewis structure for \(\mathrm{PF}_{3}\) is: \\[ \mathrm{F} : \overset{\circ}{\mathrm{F}} \mathrm{P} - \mathrm{F} : \\] This structure shows that \(\mathrm{PF}_{3}\) has three single covalent bonds between the central P atom and each of the three F atoms, with three lone pairs on each F atom.