Consider the element silicon, Si. (c) Which subshells hold the valence electrons?

Video transcript

welcome back Everyone in this example, we need to identify the sub shell that holds the valence electrons for our element chlorine. So we want to refer to first the Number of valence electrons associated with chlorine. And when we find chlorine on our periodic tables, we see that it's in group seven a. And it corresponds to atomic number 17. So recalled that atomic number is represented by the symbol Z. So this is atomic number. And because we know that that is our atomic number, recall that our number of protons are equal to our number of electrons for neutral atoms only. And so we also want to recall that our atomic number Tells us our number of protons for any atom. And so we would therefore because we have an atomic number of 17 say that we have 17 protons. And because it's a neutral atom, we have 17 electrons. Now the outer most energy levels will hold our valence electrons. So we need to figure out what that looks like by writing out our configuration of chlorine. So beginning by referring to our periodic tables, we want to start out in Group one A where we have hydrogen at atomic number one and We want to find where chlorine is located out on the periodic table. So as we stated earlier, it's in group seven a. But it's located across period three. So that's going to cover three different types of orbital's for our configuration. Our first orbital beginning where hydrogen starts is our s orbital and recall that I only consist of just one orbital, we then will have to pass through our p orbital where Adam's boring through flooring are located on our periodic table. And recall that that p orbital consists of a total of three orbital's where we next will hit chlorine in the third period of a periodic table in our third energy level of R. P block. So because we are focusing on these two types of orbital's, we want to recall the maximum number of electrons that they can hold. So because the s orbital is only one orbital recall that it only holds a maximum of two electrons that we can fill in. And because the p orbital consists of a total of three orbital's recall that it can only hold a maximum of six electrons. So let's get into our configuration, recognize that at hydrogen passing all the way through helium in the first period of our periodic table, we will fill in our first energy level of R. S orbital where we fill in for both two electrons to get through our configuration so we can land on our adam chlorine. We then move into the second period of our periodic table into the s orbital still where we pass through Adam's lithium and beryllium to fill in for those two electrons moving on in our configuration, we're still at the second period or second energy level of our periodic table. But then we hit the p block where again we stated, boring through flooring and then neon are located at where we want to fill in a total of all six electrons in these three orbital's. So that gives us our expanded of six. Moving forward in our configuration, we get to the third energy level or third period of our periodic table where we hit the S. Block passing through adam's sodium and magnesium. So we have three S. And then too, because we need to fill in for both of those electrons. And then finally at the third period of our periodic table, we hit our P block as well where we passed through adam's aluminum and then we land on our atom chlorine. And so we're going to fill in as three P. And then we would count for a total of five units where we hit our atom chlorine. So we would have three P. Five to land on our atom chlorine. And so what that means is that our p block for our configuration of chlorine is filled in as follows where we have 1234 and then five where one of our P orbital's only contains one electron. And recall that we filled this in according to poly exclusion principle, which is why we fill in all electrons singly first before pairing them up. Doubly so as we stated, we need to identify which contains our valence electrons in our configuration. And so we want to recognize that again, our valence electrons are located in the outermost energy level. And so we want to focus on our configuration, that consists of the highest energy levels and that would be our three s and then three p orbital's here. So that means that the exponents there representing our electrons filled in would be two and five as our valence orbital. Whereas everything below that would be our core electrons where we have six electrons, two electrons and two electrons in the two S and one S and then two P orbital's. So these are our core electrons also recognize that we can simplify our configuration by finding the noble gas that proceeds are adam chlorine on the periodic table to cover our electrons covering from one all the way up to two P on our configuration, meaning that that noble gas would correspond to the atom neon on our periodic table in brackets. Now, since it comes before chlorine, where we would continue our configuration as three S, two and then three P. Five. So this is our shorthand configuration and as we stated, two and five represent our valence electrons in our valence orbital's three S and three p. And so we would have the three S and three p orbital's Hold our five valence electrons for neon. And so this statement here is going to be our final answer to complete this example. And actually to be even more specific, let's use the word sub shells here. So three S and three p sub shells hold our five valence electrons for neon because we're talking about these as a whole. So everything highlighted in yellow is our final answer. If you have any questions, please leave them down below, and I'll see everyone in the next practice video.