What is the Lewis dot structure for PF5

General
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What is the Lewis dot structure for
PF5

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What is the Lewis dot structure for PF5?

Answer: The Lewis dot structure for phosphorus pentafluoride (PF₅) represents the bonding between phosphorus (P) and fluorine (F) atoms and the lone pairs of electrons that may exist in the molecule. Here is a step-by-step guide to drawing the Lewis dot structure for PF₅:

1. Count the Total Valence Electrons:

  • Phosphorus (P) is in group 15 of the periodic table and has 5 valence electrons.
  • Fluorine (F) is in group 17 of the periodic table and has 7 valence electrons each.
  • There are five fluorine atoms, contributing a total of (7 \times 5 = 35) valence electrons.
  • Therefore, the total number of valence electrons for PF₅ is (5 + 35 = 40) valence electrons.

2. Determine the Central Atom:

  • The central atom is typically the atom that can form the most bonds, which is usually the least electronegative atom. In PF₅, phosphorus is the central atom.

3. Arrange the Atoms and Place Bonding Electrons:

  • Place phosphorus in the center and arrange the five fluorine atoms around it.
  • Place a single bond (2 electrons) between the phosphorus and each fluorine atom.

4. Complete the Octets of the Fluorine Atoms:

  • Each fluorine needs 8 electrons to complete its octet. Each single bond already has 2 electrons, so each fluorine atom needs 6 more electrons.
  • Place 3 lone pairs (6 electrons) on each fluorine atom.

5. Check the Total Number of Electrons:

  • Phosphorus has 5 single bonds, meaning it is sharing (5 \times 2 = 10) electrons.
  • Each fluorine has 3 lone pairs and 1 bonding pair, totaling 8 electrons per fluorine.
  • We have 5 fluorine atoms, which contribute (5 \times 8 = 40) electrons.
  • The total number of valence electrons used is (10 + 30 = 40), which matches the number of available valence electrons.

6. Confirm the Structure:

  • Every fluorine atom has a complete octet.
  • Phosphorus, in this case, follows the expanded octet rule and holds more than eight electrons due to having access to d-orbitals.

The Lewis dot structure for PF₅ can be represented as:

    F
    |
F - P - F
    |
F - P - F
    |
    F

In this structure, phosphorus is the central atom with five fluorine atoms attached to it by single bonds. The phosphorus atom has 10 electrons in its valence shell, adhering to the expanded octet rule often applicable to elements in period 3 and beyond of the periodic table. Each fluorine atom has three lone pairs, completing their octet.

By following these steps, you have successfully drawn the Lewis dot structure for PF₅.