Using the molecular orbital model, write electron...

Using the molecular orbital model, write electron configurations for the following diatomic species and calculate the bond orders. Which ones are paramagnetic? Place the species in order of increasing bond length and bond energy.
a. CO
b. $\mathrm{CO}^{+}$
c. $\mathrm{CO}^{2+}$

Key Concepts

Paramagnetism

Paramagnetism arises when a molecule has one or more unpaired electrons in its molecular orbitals. These unpaired electrons cause the molecule to be attracted to a magnetic field. Knowing the electron configuration helps determine whether a molecule is paramagnetic or diamagnetic.

Bond Order Calculation

Bond order is computed by taking half the difference between the number of electrons in bonding molecular orbitals and the number of electrons in antibonding orbitals. This value correlates with the strength and stability of a bond; a higher bond order typically indicates a stronger, shorter bond and a higher bond energy.

Influence of Ionization on Bonding Properties

Ionization, which involves either adding or removing electrons from the molecule, alters the electron configuration. This, in turn, affects the bond order, bond length, and bond energy. Removing an electron from a bonding orbital generally decreases the bond order, while removal from an antibonding orbital can increase it, impacting both the magnetic properties and stability of the molecule.

Molecular Orbital Diagram

A molecular orbital diagram arranges molecular orbitals in order of increasing energy and shows how electrons occupy these orbitals. It distinguishes between bonding orbitals, which stabilize the molecule, and antibonding orbitals, which counteract bonding when occupied. This diagram is crucial for determining electron configurations in small molecules.

Molecular Orbital Theory

This concept involves describing the electronic structure of diatomic (and polyatomic) molecules by combining atomic orbitals to form molecular orbitals that extend over the entire molecule. It provides a framework for understanding aspects such as bond order, bond energy, and magnetic properties (paramagnetism or diamagnetism) based on the filling of these orbitals.

Electron Configuration (in MO Theory)

In molecular orbital theory, electron configuration refers to the distribution of electrons among the molecular orbitals. This configuration is used to tally the net bonding interactions in a molecule and is essential in calculating properties such as bond order and magnetism.

Transcript

00:01 Here we've just got another molecular orbital theory query.

00:05 So i've got all of the molecules that we will be considering on screen.

00:09 I've also got the bond orders, whether they're parrot or diamagnetic, and the fact that we have the downward trend of a decrease in stability.

00:20 And now we know that because our bond orders are decreasing as we move down.

00:25 So i'm going to run through our first example here.

00:28 We've got carbon monoxide.

00:29 I'm going to rationalize.

00:30 How we have identified the bond order as well as the fact it's diamagnetic and then you use the same rationale through the next two molecules so we've got co here oxygen's more electro -negative so the orbitals are a slightly lower energy because it is more stabilized so carbon we are populating with four electrons across our one two three four across our two s and two p two p two 2s, 2p.

01:04 Oxygen, we are populating 6, is in group 6.

01:08 1, 2, 3, 4, 5, 6.

01:12 We can now throw the electrons that we have in our atomic orbitals into our molecular orbitals.

01:18 So we can add them up.

01:20 We've got 6 add 4.

01:21 We're throwing 10 electrons into this centre.

01:25 1, 2, 3, 4, 5, 6, 7, 8, 9, and 10.

01:34 So you can see that it's diamagnetic...

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