Explain why the properties of boron differ so markedly from the properties of the other group 3A elements.

Video transcript

All right. Hi, everyone. So this question is asking us which of the following statements, explains the differences between the properties of boron and the other group three A elements. Now this question has four answer choices in total three of which I'm going to read as we progress through this video because I want to analyze each of them individually. Though option D simply says all of the above. Now recall first and foremost that the group three A elements consist of the following. We've got boron, aluminum gallium India and sal you. So let's keep them in mind as we start off with analyzing option A option A says that boron is a good semiconductor because it is a semi metal. While other group three A elements are good conductors because they are metals. Now recall that this statement is actually accurate, right? Because of the group three A elements that I've listed here boron is the only semi metal, whereas aluminum gallium indium and thallium are in fact metals. Now, metals are known for being good conductors of electricity, whereas semi metals fall somewhere in between metal and nonmetal. So when used as semiconductors, it's generally because they have less conductivity than metals, but more so than non metals. So option A is actually correct. Now, let's move on to option B boron only forms molecular compounds due to its high ionization energy. While the other three A elements form ionic compounds due to their lower ionization energy. No recall, it ionization energy actually decreases as you go down a group. So boron being at the very top of group three A is going to have the highest ionization energy of our group three A element. And this makes sense, right? Because number one boron is not a medal, which means that it can't actually become a cat ion at any point, right. And the reason for this is because the ionization energy or the energy required to remove an electron from a given atom is remarkably high for boron compared to the other elements listed here. So because of this, it's remarkably difficult for boron to lose an electron and become an ionic or an ion, excuse me. So therefore, boron can only form covalent or molecular compounds in which electrons are being shared and not lost. So option B is actually correct as well. And last but not least we have option C option C says that boron has a higher melting point due to its smaller atomic radius. While the other group three A elements have a lower melting point due to their larger atomic radius. So recall the melting point of any given element can be determined by its atomic radius. Now, for the record, the atomic radius is going to increase as we go down the group, which means that boron has the smallest atomic radius. Whereas thallium has the largest in group three A right now, the melting point of the element or MP for short actually increases as the atomic radius get smaller, right. And the reason this is the case is because as the atomic radius gets smaller, electrons are more delocalized, which makes the melting point higher overall. So because boron has the smallest atomic radius, it will in turn have the highest melting point. So option C is actually correct as well, which means that all three statements we discussed previously are actually accurate. Therefore, our answer is going to be option D in the multiple choice, which is all of the above statements A B and C correctly differentiate boron from other group three A elements. So with that being said, thank you so very much for watching. And I hope you found this helpful.