Draw a lewis dot structure for BrF4+. Place overall charge on the central atom.
The correct answer and explanation is :
To draw the Lewis dot structure for the ( \text{BrF}_4^+ ) ion, follow these steps:
Step-by-step process:
- Determine the number of valence electrons:
- Bromine (Br) is in group 17 (halogen group), so it has 7 valence electrons.
- Fluorine (F) is also in group 17, so each fluorine atom has 7 valence electrons. Since there are 4 fluorine atoms, the total number of valence electrons from fluorine is ( 4 \times 7 = 28 ).
- The positive charge on ( \text{BrF}_4^+ ) means that one electron has been removed, so the total number of valence electrons is ( 7 + 28 – 1 = 34 ).
- Determine the central atom:
- Bromine (Br) is less electronegative than fluorine (F), so it will be the central atom.
- Arrange the atoms:
- Place bromine in the center, surrounded by the 4 fluorine atoms.
- Distribute the electrons:
- Each fluorine atom needs 2 electrons to form a single bond with bromine. So, we use ( 4 \times 2 = 8 ) electrons for the bonds.
- The remaining electrons will be placed around the atoms as lone pairs. Initially, place the remaining 26 electrons (since 8 electrons have already been used for the bonds) as lone pairs around the fluorine atoms.
- Place the remaining electrons on the central atom:
- After bonding and placing the lone pairs on fluorine, there are 26 electrons left. However, bromine can hold more than 8 electrons in its valence shell (due to being in period 4), and it will take more electrons to satisfy its octet (or in this case, a more stable expanded octet).
- Place the remaining electrons around the bromine to complete its octet. In this case, the bromine atom will have 12 electrons in its valence shell, which is acceptable for atoms in period 4 or higher.
- Consider the charge:
- The positive charge on ( \text{BrF}_4^+ ) is indicated by removing one electron, so the overall charge will be placed on the central bromine atom.
Final Lewis structure:
The structure of ( \text{BrF}_4^+ ) shows bromine in the center with four single bonds to four fluorine atoms. Bromine has 12 electrons in its valence shell (12 because it needs to expand its valence shell to accommodate 4 bonds), and the overall positive charge is placed on the central bromine atom.
Explanation:
- The structure has bromine at the center with 4 single bonds to fluorine atoms, satisfying the valence requirements for fluorine. Each fluorine atom has 3 lone pairs, making it stable with 8 electrons in its valence shell.
- The bromine atom has an expanded octet, which is possible because bromine is in period 4 and can accommodate more than 8 electrons. In this case, bromine holds 12 electrons in its valence shell.
- The overall positive charge indicates the loss of an electron, which is placed on the central bromine atom.