What is the lewis dot structure for IBr4-?
To determine the Lewis dot structure for IBr4-, we need to consider the valence electrons of each atom and then distribute them around the central atom.
1. Count the total number of valence electrons:
Iodine (I) is in Group 7A and has 7 valence electrons.
Bromine (Br) is in Group 7A and has 7 valence electrons.
For the negative charge (-) of the ion, add one additional electron.
So, the total number of valence electrons is 7 (Iodine) + 7 (each Bromine) + 1 (negative charge) = 15.
2. Identify the central atom:
In IBr4-, iodine (I) is the central atom since it is less electronegative compared to bromine (Br).
3. Connect the peripheral atoms (bromine) to the central atom (iodine) with single bonds (represented by a pair of electrons). Each bond will require 2 electrons.
Thus, we already have 4 bromine atoms bonded to iodine, accounting for 4 x 2 = 8 electrons.
1 attach: Br-I-Br
2 attach: Br-I-Br
3 attach: Br-I-Br
4 attach: Br-I-Br
After placing the remaining electrons, we can see if we have satisfied the octet rule for all atoms:
- Remaining electrons = 15 (total valence electrons) - 8 (used to form bonds) = 7 electrons.
4. Distribute the remaining electrons around the outer atoms (bromine) to satisfy the octet rule. Each atom wants 8 electrons, so place one electron as a lone pair on each bromine atom.
1 attach: Br-I-Br (lone pair Br)
2 attach: Br-I-Br (lone pair Br)
3 attach: Br-I-Br (lone pair Br)
4 attach: Br-I-Br (lone pair Br)
5. If there are any remaining electrons, place them on the central atom (iodine) as lone pairs.
Since we still have additional electrons, we place two lone pairs on the central iodine atom.
1 attach: Br-I-Br (lone pair Br)
2 attach: Br-I-Br (lone pair Br)
3 attach: Br-I-Br (lone pair Br)
4 attach: Br-I-Br (lone pair Br)
(2 lone pairs I)
6. Check the final structure to ensure that all atoms fulfill the octet rule.
In this case, iodine has 8 electrons (2 from lone pairs and 6 from bonds), and each bromine atom has 8 electrons (2 from lone pairs and 6 from bonds).
Thus, the Lewis dot structure for IBr4- is:
Br-I-Br
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Br-Br