Propose structures for molecules that meet the following

descriptions.

(c) Contains an S atom that has a coordinate covalent bond

Video transcript

All right. Hi everyone. So this question says to determine the molecule that contains a selenium atom with a covalent coordinations bond. Option A says one, option B says two, option C says three and option D says none of the above. Now recall first and foremost, that coordinate bonds or co-ordination bonds can also be referred to as native covalent bots. Now recall that the average covalent bond is formed when two atoms share a pair of electrons in between them. However, coordinate bonds are a little bit different in the sense that in a coordinate bond, the electron is being shared between two atoms originate from the same matter. So instead of having both atoms contribute one electron towards the covalent bond in a coordinate bond, both electrons shared originate from the same atom. Now, selenium is part of group six A which means that it has six valence electrons as well as a maximum oxidation state of positive six. Now, that means that silly num can form a maximum of six coated bonds. So now let's go ahead and examine compound one in which selenium has two bonds to chlorine as well as only one to oxygen. Now, chlorine being a halogen belongs to group seven a of the periodic table, meaning it has seven valence electrons. So here, both chlorine atoms have three lone pairs of electrons as well as one bond to sele. So that means that selenium and chlorine contribute one electron each towards the bond that is being formed here. So the bonds between selenium and chlorine in compound one are not going to be coordinate bonds, but the same cannot be said for oxygen because we call it oxygen is also a part of group six A, meaning it also has six valence electrons. However, here are oxygen atom has three pairs of electrons in this case. So even though it has six valence electrons, it did not actually share any of them to form the bond with selenium, which means that selenium contributed the electrons to bond with oxygen because we can see that oxygen still has its six pence electrons, meaning it did not share them with selenium to create the bond. So compound one does in fact have a covalent co-ordination bond between selenium and oxygen. Now, on the other hand, if we consider compound two compound, two has three bonds between selenium and three oxygen atoms, now these oxygen atoms, all three of them, in the case of compound, two have two loan pairs of electrons and a double bond between itself and selenium. Now this means that in order to create the bond with selenium, each oxygen atom must have contributed its valence electrons towards the bond with selenium. Because notice how it only has two lone pairs each of them. So each oxygen has four electrons and an additional two if you consider each double bond to selenium. So in this case, selenium and oxygen or in other words, molecule two does not have a co coordinate covalent bond and neither does compound three right, because compound three involves a bond between hydrogen and selenium and chlorine and selenium. Now, as we can see in the first example, chlorine did, in fact, sheer one valence electron to create a bond with selenium, because chlorine has seven valence electrons, six of them come from the lone pair surrounding it. And one of them contributes towards the bond between itself and selenium. Now hydrogen hydrogen only has one electron or one valent electron, right, which means that it's easily going to contribute its electron towards a bond with selenium because recall that hydrogen is only capable of forming one covalent bond for this reason. So this means that compound three does not have a covalent co-ordination bond either. So our here will be option a in the multiple choice because only compound one contains a covalent co ordination bond and there you have it. So with that being said, thank you so very much for watching. And I hope you found this helpful