What is the general trend in standard potentials for the oxidation of first-series transition metals from Sc to Zn? What is the reason for the trend?

Video transcript

Alright. Hi, everyone. So for this question, let's predict the general trend in standard oxidation potentials for the elements from atrium to cadmium. Justify your answer. And here we have four different answer choices. Each alternating whether or not the trend increases or decreases depending on a number of different reasons. Right? So recall first and foremost that atrium and cadmium are both transition metals that happened to fall in the same period or in the same row on the periodic table. So atrium is further to the left side and cadmium is further to the right side. Now recall that when it comes to an oxidation oxidation refers to a loss of electrons, right? And you can recall this through a number of different acronyms. You can recall either Leo G or oil rig, but both acronyms illustrate the same principle, right? That oxidation involves a loss of electrons, whereas reduction involves a gain of electrons, no, the tendency for an element to undergo oxidation. In other words, the tendency for an element to lose electrons is related to a few different factors. One is atomic radius, two is effective nuclear charge or Z effective, right? And the third is ionization energy. So by illustrating the trends of these three variables, we can better understand the trend that we would expect to see for the standard oxidation potentials. Now, just for the record, right, because atrium and cadmium are in the same row or the same period of the periodic table. I'm going to focus on each trend going from left to right and not up and down. In this case, starting off with the atomic radius right now, recall that the atomic radius is generally going to increase as I go from right to left across a period, right. So here atomic radius is going to increase as I go from cadmium to the right side towards atrium on the left side. Now, the second charge that I want to discuss right now involves the effective nuclear charge. Now recall that effective nuclear charge is the magnitude of a positive charge in an atom. And unlike the atomic radius, the effective nuclear charge is going to increase as we go from left to right across a period. Now, the last trend to focus on in this case is ionization energy and recall that ionization energy refers to the amount of energy required to remove an electron from any given atom or molecule. And so the trend for ionization energy happens to be the same one as the trend for effective nuclear charge because in this case, ionization energy is going to increase from left to right as well. So with this information on hand here, what we'll notice is that atoms with a smaller atomic radius are going to experience a greater effective nuclear charge as well as a greater ionization energy. Because cod beam, for example, being farther to the right, in this case is going to be smaller and that it has a smaller atomic radius and it also has a greater effective nuclear charge as well as a greater ionization energy. So all this is to say right is that cadmium not only has a smaller atomic radius, it has a higher ionization energy which means it is less likely to lose electrons. So, because oxidation involves the loss of electrons, the oxidation potential of cadmium is going to be less than that of atrium. Therefore, right, the standard oxidation potential from atrium to cadmium decreases because the effective nuclear charge and ionization energy increase while the atomic radius decreases. So our final answer is going to be option d in the multiple choice and there you have it. So with that being said, thank you so very much for watching. And I hope you found this helpful.