Using the periodic table as a guide, write the condensed electron configuration and determine the number of unpaired electrons for the ground state of (d) As.

Video transcript

everyone in this example. We need to choose the correct shorthand electron configuration. And number of unpaid electrons for the adam bro mean? So we want to recall that the shorthand electron configuration is a K. A. Our noble gas configuration. So what we want to do is find boron or sorry, bromine on the periodic table. And we would recall that bromine is located across period four In Group seven a. of our periodic table. So because we want to use the shorthand or noble gas electron configuration, we want to find the noble gas that comes before period four where browning is located and that would correspond to our noble gas on period three which is are gone. So we would begin our configuration with argon in brackets. And after we pass argon on the periodic table, we can move on to period four where bromine is located and recognize that to get through its configuration, we need to fill the S sub level up which we should recall can hold a maximum of two electrons. So we would have Four because we're at the fourth energy level being at the 4th period of our periodic tables. Us too. So once we fill up our s sublevel, we move into our D block or transition metal section of our periodic table. And we should recall that our D block because it has a maximum of five orbital's can hold a total of 10 electrons. And so we should recall that our D block at the fourth period of our periodic table begins at the third energy level. So we would have three D. And then again we said it can hold a maximum of 10 electrons. So we would fill in 10 in our exponent here. And lastly, once we fill up our D block, we head into our P block of our periodic table, which is where bromine is located, because it's in group seven A. And so we should recall that this would still begin at the fourth energy level because we are in the fourth period of our Periodic table. So we would have four p. And then we would count for three units. Or sorry, we would account for five units in the P block in order to land on our adam bro mean. So we would have five as the exponent here in our configuration. Now we want to make sure that we have our configuration written out in order of ascending energy levels. So we want to start out with the lowest energy level first when writing out our configuration. So we should go ahead and actually write this. So that we have Argon three D since it's at the third energy level, we're starting out with the lowest energy level. Then we should recall that our S sublevel is smaller than our P sub level because again R S sublevel only holds a maximum of two electrons. So we would write out four s to next. And then lastly we complete our configuration with the highest sub level and energy level at four P five. And this here is going to be our final answer to complete this example for our electron configuration for browning Now. Our next answer for this example should be our number of unpaid electrons. So if we go ahead and imagine our p orbital, we should go ahead and recall that it has a total or rather our peace sub level, we should recall. It has a total of three orbital's so we're going to represent the orbital's by these lines here and we filled in a total of five electrons in this p orbital which we recall Can hold a maximum of six electrons. Now we have to follow the poly exclusion principle when filling in these electrons. So we fill in each orbital with an electron one by one. So we would have one, 2, 3 and then now we can go ahead and pair the electrons up with the opposite spin. So we would have four and then five and so as you can see because we filled in our five electrons because we counted five units in the p sub level or P block to land on our adam bro, mean we're left with one unpaid electron here. So we would say for our second part of our final answer that we have one um paired electron in our p orbital. And so this would also be our second final answer to complete this example fully for our configuration of bromine. So I hope that everything I explained was clear. If you have any questions, please leave them down below. Otherwise I'll see everyone in the next practice video.