00:01
To draw the lewis structure for mangana, we recognize that it is mn04 minus.
00:06
We'll count the total number of valence electrons.
00:10
Manganese has two valence electrons in the 4 -s sub -level and five valence electrons, which we often loosely call valence electrons that are in a 3d sub -level.
00:23
So we would say it has a total of 7.
00:25
We would then add to that 6 times 4.
00:31
Oxygen has 6 valence electrons, and there are 4 of them, plus one more because of the negative charge.
00:39
This then gives us a total of 32 valence electrons.
00:45
If we put manganese in the middle, and we bond four oxygens to it, and we give each oxygen three lone pairs, we would have used up all 32 of the valence electrons.
01:01
However, the formal charge on manganese and oxygen are not zero.
01:09
To get them to be closer to zero, we need to have three oxygens share a lone pair to form double bonds, resulting in an expanded octet for manganese.
01:25
But this is what is required in order to reduce the formal charge to zero.
01:33
Formal charge is equal to the number of valence electrons minus the number of assigned electrons.
01:47
Oxygen has six valence electrons.
01:50
With the double bonds, we have one, two, three, four...