Arrange the following atoms in order of increasing effective nuclear charge experienced by the electrons in the n = 2 shell: Be, Br, Na, P, Se.

Video transcript

welcome back everyone. We need to consider the following elements indium tin, zirconium to Laurie. Um And strontium we have to list these elements from the most to least effective nuclear charge experienced by the electrons at the third energy level shell. So because the prompt gives us our energy level being the third show, we would say that the third shell would consist of our will say valence electrons. So this is otherwise known as our valence shell. And recall that our valence electrons are our outermost electrons making up the configuration of each of our atoms here. So because we understand that our valence shell is the third energy level. That would mean that our one s to us and to p sub shells would be our core electron shells. And because we recall that our effective nuclear charge tells us the amount of positive charge experienced by an electron for each of our atoms. We would recall that the electrons in these lower energy level sub shells. So the one S, two S. And two P in this case are shielding or they shield the electrons in our third energy level. So in an equals three and they do so equally. So these lower level electrons equally shield the higher or valence shell electrons from attaining that nuclear charge or the charge of the nucleus which is a positive charge in each of our atoms. Because we should recall that our nucleus contains the protons of our atoms. And because we recall this fact we can say that therefore our effective nuclear charge of our atoms increases as our atomic number of our atom increases. And recall the atomic number is represented by the symbol Z. And we are relating this to atomic number because we should recall that our atomic number tells us our number of protons which is also related to our number of electrons in a neutral atom. And so because we have all neutral atoms given, we can make note of each of our atomic numbers for each of our given elements to determine our ranking for most to least effective nuclear charge. So beginning with our first atom we have we will see on our periodic tables that our first element indium has the atomic number 49. So we'll make note of that above. Moving on we have our element 10 which we see corresponds to the atomic number 50 on our periodic tables. Then we have zirconium which on our periodic tables we see corresponds to atomic number 40. Then after that we have to Laurie um which we see corresponds to atomic number 52. And then then we have strontium listed, which on a periodic tables we see corresponds to atomic number 38. So these are all of our Z values or atomic number values for each of our given elements. And now that we have this ordering we can again list from highest effective nuclear charge to lowest effective nuclear charge by recalling again that as effective nuclear charge. Or sorry as atomic number increases are effective nuclear charge increases. And so beginning with our highest atomic number we see that that corresponds to our adam to lori. Um So that would correspond to also having the highest effective nuclear charge in our ranking. And so that would be listed first. So we have to Laurie um Then in our ranking for the second highest atomic number that would correspond to our adam tin which we see has atomic number 50 meaning it also has a high effective nuclear charge. So we would say instead of a comma the effective nuclear charge of Tillery um is going to be greater than our effective nuclear charge of 10 because 10 has the lower atomic number being 50. And so it has the lower effective nuclear charge dan Tillery. Um And then our third highest atomic number is going to be Our atomic number for indium which we see has the value 49. And so we would say that tin has a great of effective nuclear charge than India and let's just make some more room in our ranking since we have some more elements to list. So after after Indian we would say Indian has a greater effective nuclear charge than our atomic number for zirconium which is 40. So we would say it has a greater effective nuclear charge them zirconium and then after zirconium we would be left with atomic number 38 corresponding to our atom for strontium which has the lowest effective nuclear charge. And so for our final answer, which is our ranking here that we're going to box in. We have the highest effective nuclear charge for the atom to Laurie, um and the lowest effective nuclear charge for adam strontium. And this is what would be experienced by our electrons in the third energy level of each of these atoms. So this is our final answer box in yellow. I hope that everything I reviewed was clear. If you have any questions, please leave them down below and I will see everyone in the next practice video.