Arrange the atoms according to decreasing effective nuclear
char...

Question

Arrange the atoms according to decreasing effective nuclear 
charge experienced by their valence electrons: S, Mg, Al, Si.

Accepted Answer

Hey everyone in this example, we need to list the below elements from most to least amount of effective nuclear charge affecting their valence electrons. So we should recall that this symbol here, Z. F. Stands for effective nuclear charge and this is a trend on our periodic tables. That we should recall is going to be increasing as we go from the bottom and towards upward towards the right on our periodic table. So what we're going to want to do is compare the positions of these atoms on our periodic table. So we have selenium versus bro, mean versus potassium vs gallium. And so for selenium we would recall, we can find it in Group six A. On the periodic table across period four. And actually I'll just right across here so that I don't have to keep rewriting it. So we would find, yes, selenium across period four. In group six a. Now compared to selenium mm we would find in Group seven A. On the periodic table Also across period four. Then potassium we would find in group one a on our periodic table Also across period four. And lastly we have gallium which we would find in group three a. On our periodic tables Also across period four. And so therefore we would conclude that based on our spectrum of labeling from the highest effective nuclear charge to the least effective nuclear charge. We're going to go ahead and put the adam with the most effective nuclear charge as the one that is most towards the right of our periodic table. So it should be in a group number that brings it more to this side of our periodic table because they're all in the same period. So we can't base it on what's higher or lower. So in that case we would go ahead and list bromine first because it's in group seven a. Which we should recall is pretty much next to Our noble gasses here in group a day. So seven a. Would be over here which is pretty far to the right. And so we would say that it has the greatest effective nuclear charge in comparison to the second most atom with the effective nuclear charge of Sorry with the atom that has the second most high effective nuclear charge. And that would be selenium because it's in group six a. Then after selenium we would have gallium listed next because it's in group three a. And lastly that leaves us with potassium as the atom with the least effective nuclear charge Because it's only in group one a. Which we know is the first group on our periodic table. So it's towards um it's the least towards the right and all the way to the left of our periodic tables. So it has a very low effective nuclear charge value. And so this would coordinate with choice B out of our multiple choice and this is our final answer. To complete this example. If you have any questions, please leave them down below. And I will see everyone in the next practice video

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