The following diagrams represent the electron population of molecular orbitals for different substances. What diagram corresponds to magnesium oxide, germanium, and tin? (LO 12.8)

(a) Diagram 1 = tin, diagram 2 = magnesium oxide, diagram 3 = germanium (b) Diagram 1 = germanium, diagram 2 = magnesium oxide, diagram 3 = tin (c) Diagram 1 = germanium, diagram 2 = tin, diagram 3 = magnesium oxide (d) Diagram 1 = magnesium oxide, diagram 2 = tin, diagram 3 = germanium

Video transcript

Hello everyone today. We have the following problem. The electron population of molecular orbital's for various compounds is shown in the graphs below which of the following diagrams corresponds to aluminum oxide, gallium arsenide and mercury. So essentially we are being asked to differentiate between these three medals. An important thing to recall with medals is that metals essentially have an overlap between conduction and valence bands. So there's gonna be some sort of overlap between these two things. And so the next thing we have to keep in mind is what are some properties of metals. So metals can either be insulators or conductors or semiconductors. Insulators tend to have a very large band gap between the bands. And the reason for this is that insulators are very poor conductors of electricity. So there's no overlap, meaning that the electrons cannot transfer over. Next. We're going to focus on what a conductor would be. Conductors essentially have a not extreme overlap, but the overlap is present between between the bands. So it's going to be a clear marking where the valence band meets the conduction band. And then after conductors, you might have some metals that are considered semiconductors that aren't the best conductors of electricity, but they also aren't the worst. And they can still conduct electricity. And semi conductors have a very, very small band gap. And so at a specific specific energy, they can essentially jump from the valence band into the conduction band. So at specific energies at specific energies the band is so small that electrons can migrate into the conduction band and the conduction band will have a higher energy. Right? So we can count that are red band here is going to be the valence band. It's lower energy and our blue band is going to be our conduction band. So if we look at diagram a if you look at diagram a we see that there is a very large gap. And so what does this correspond to this corresponds to an insulator. And so the only metal here that's present that could be an insulator is going to be our gallium arsenide. So we have part of our problem solved diagram A is gallium arsenide. If you look at diagram B, we see that diagram B has a very small band gap that allows electrons to migrate at a certain temperature indicated by the arrow below. We're in the diagram. And so this lines up perfectly with a semi conductor. Remember semiconductors, as we stated before, have a very small band gap that allow electrons to pass on at specific energies. And so the only semiconductor here is going to be gallium arsenide. Earlier, I stated that an insulator would be gallium arsenide, but this is not true. An insulator in this case would be aluminum oxide. Aluminum oxide is a relatively poor conductor of electricity, it does not allow electrons to migrate through material. On the other hand, gallium arsenide is a semiconductor. So it's partially good, partially not that well at conducting electricity. And lastly we are going to look at diagram, see if you look at diagram, see there's essentially no gap, There is a complete overlap. And as we said before, this is the perfect definition of what a conductor is. And if we see the only metal left is mercury, it's a pure metal. So of course it is going to be purely a conductor and have no interference. Overall, I hope that this helped, and until next time.