To draw the Lewis structure for the hypobromite ion (BrO⁻), follow these steps:
Count the Total Valence Electrons
First, determine the number of valence electrons:
- Bromine (Br) has 7 valence electrons.
- Oxygen (O) has 6 valence electrons.
- Since the ion has a negative charge (BrO⁻), add 1 more electron.
This gives a total of 7 + 6 + 1 = 14 valence electrons.
Arrange the Atoms
Next, place the bromine atom in the center and connect it to the oxygen atom:
- Br is less electronegative than O, so it goes in the center.
- Connect Br and O with a single bond.
Distribute Remaining Electrons
After forming the bond, you have 12 electrons left to distribute:
- Place 6 electrons (3 lone pairs) around the oxygen atom to satisfy its octet.
- This uses up 6 of the remaining electrons, leaving you with 6 electrons.
Complete the Octet for Bromine
Now, place the remaining electrons on the bromine atom:
- Add 3 lone pairs (6 electrons) to Br.
- This gives Br a total of 8 electrons, completing its octet.
Check Formal Charges
Finally, ensure that the formal charges are minimized:
- For Br: 7 (valence) - 0 (bonds) - 6 (lone pairs) = +1.
- For O: 6 (valence) - 2 (bonds) - 4 (lone pairs) = 0.
The overall charge of the ion is -1, which is consistent with the hypobromite ion.
Final Structure
The Lewis structure for the hypobromite ion shows a single bond between Br and O, with Br having three lone pairs and O having one lone pair:
Br: 3 lone pairs, O: 1 lone pair, and a single bond between them.