Why does the molecular orbital model do a better job in explaining the bonding in NO^- and NO th

Why does the molecular orbital model do a better job in...

Key Concepts

Bond Order and Electron Distribution

Bond order provides a quantitative measure of the strength and number of bonds between atoms, calculated from the difference between the number of electrons in bonding and antibonding molecular orbitals. Molecular orbital theory naturally accommodates calculations of fractional bond orders, which are essential for accurately describing molecules where electron sharing does not equate to a simple integer value, offering deeper insights into the electronic structure of species like NO and NO?.

Hybrid Orbital Theory

Hybrid orbital theory focuses on the mixing of atomic orbitals on the same atom to explain molecule geometry and localized bonding patterns. While useful for many molecules, it lacks the framework to account for electron delocalization and long-range interactions across a molecule. This limitation makes it less effective for molecules with non-standard electron counts or significant bond delocalization, such as NO and its anion.

Molecular Orbital Theory

This theory treats electrons as delocalized over the entire molecule rather than being confined to individual bonds. Unlike localized bonding theories, it explains phenomena such as bond order, magnetism, and the presence of delocalized electrons by constructing molecular orbitals from linear combinations of atomic orbitals. It is particularly effective at describing molecules with unpaired electrons or those with an odd number of electrons, such as NO, by considering both bonding and antibonding interactions globally.

Transcript

00:01 So here we're just going to be considering our orbital theories, and specifically we're going to be looking at the limitations of some of our theories.

00:11 So we've got an example here of no and no minus.

00:16 And so molecular orbital theory better explains some molecules better than that hybrid orbital theory does.

00:25 So the hybrid orbital theory system can explain molecules with all paired electrical.

00:31 However, it is rather poor at explaining molecules that do have unpaired electrons.

00:39 And so instead, m .o theory is used to explain molecules that do have unpaired electrons, as the data we generate from our mo theory agrees with our experimental data.

00:51 And the hybrid orbital theory doesn't always highlight the differences in bond strength between no and no minus.

00:57 And so instead, we use mo theory.

01:01 And then i've got our diagrams drawn out here to save us time.

01:07 Let me just quickly move this diagram as we've cut off an orbital.

01:15 So now we can go ahead and start filling our orbitals.

01:19 So we know that nitrogen is group 5, oxygen, group 6.

01:25 So all we need to do is throw in these electrons.

01:29 So we can, our nitrogen can be on the, left or oxygen can be on the right so one two three one two three four five and again for oxygen group six so we've got six electrons one two three four five six and remember to singly occupy your orbitals before then pairing them okay so now what we need to do is take our electrons from our atomic orbitals and we need to just throw them into our molecular orbitals.

02:08 So here we've got a bonding and an anti -bonding.

02:12 And now we have one, two, three, four, five, six, seven electrons i need to populate here.

02:18 One, two, three, four, five, six, seven.

02:26 So now we can figure out our bond order.

02:29 So we know that our bond order is our bonding order...

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