12. Molecular Shapes & Valence Bond Theory
MO Theory: Bond Order
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Using m o theory and bond order, determine the number of bonds connecting the nitrogen atoms within the n two two minus ion. Alright. So remember we said that if you have a single bond, it's 1. If it's double bond, it's 2. Here though, we don't have an actual visualization of the bond between the 2 nitrogens, so we're gonna have to use our MO diagram. Since we're dealing with nitrogen, remember that would be, what, sigma 2s, sigma star 2s, pi2p, sigma2p, pi star 2p, and then finally, sigma star 2p. Here, nitrogen is in group 5a, so it has 5 valence electrons, and there are 2 nitrogens so that's 5 times 2, which is 10, and then we have an additional 2 electrons. So add 2 to this, this is 12. So all we gotta do now is fill in those electrons. 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, and then 12. And then remember here bond order, which we're gonna abbreviate as b o, equals half of your bonding electrons. So your bonding electrons would be 2, 4, 6, 8. So you have 8 bonding electrons minus your anti bonding electrons, the ones with the star. So 2, 4. So we do 8 minus 4 which is 4 times a half gives me 2. So the bond order between the 2 nitrogens would be 2. And if we wanted if I wanted to show you what this would look like, it looks like this. This is what the ion actually looks like. And we can clearly see that there's a double bond between the nitrogens, so this visualization is definitely reinforced by the fact that we found a bond order of 2. So that means there's a double bond between the 2 nitrogens. Right? So we'd say then determine the number of bonds be connecting the 2 nitrogens, we'd say that they're connected by a double bond.
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