Valence Electrons of Elements

now when it comes to Valence, electrons were going to say that for main group elements. So basically not the transition metals were going to say the number of Valence electrons equals the group number of the element. When we say valence electrons, the valence electrons are just your outer shell electrons involved in forming chemical bonds. The inner core electrons are just all the remaining electrons that are not valence electrons. And we're going to say here that your atomic number can be thought of as your total number of electrons and that equals just all your valence electrons, plus your inner core electrons. If we take a look here we have chlorine. Chlorine is in group seven A. So it has seven valence electrons. It's electron configuration is one s to to us to two p 63 s 23 p five. Here. Remember, the number in front tells us the shell number. So here this will be shell one shell to and shell three. If we have a representation of the atom like we do here, the first shell has two electrons in it. The second shell, and equals two has a total of eight electrons in it. So if you count all the way around. And then we can say here that the outer shell has seven electrons total in it. So let's add the additional two electrons that we need. So we have one, 2345 six, and then seven. Those are our seven total electrons. So here we have the visual representation of the atom or using the electron configuration to justify this representation of the chlorine atom. But for simplicity, just say group number of the Element main group element is 78 so it has seven valence electrons. If you subtract that, then what's left will be your inner core electrons. Yeah, which would just be 10. And we would see Yes, In fact, it is 10. Because when you add up these numbers, it gives you 10. And when you look at the visual representation of the chlorine atom, you'd also see that there are 10 inner core electrons

here, it says. How maney inner core and valence electrons, which would a silicon Adam possess? So Adam means that it's a neutral element, and when we look, silicon has an atomic number of 14 on the periodic table. So remember your atomic number, which is connected to your total number of electrons, equals your valence electrons. Yeah, which form a group element, is just your group number, plus your inner core electrons here, the atomic number. Again, we said it's 14. Silicon is in Group four A. On the periodic table since it's in Group four. A. It has four valence electrons, so we already know we have four Valence electrons. Okay, and all we have to do here to find the number of inner core electrons is subtract four from both sides, and what's left is 10 that 10. What equal the number off in our core electrons? Yeah, so we'd say that's the silicon. Atom has four valence electrons, instant group for A, and it has 10 inner core electrons

now with transition metals were going to say the number of Valence electrons equals their outermost s orbital electrons, plus their deep orbital electrons. And here remember your transition Metal elements are known as your group B elements, so we know there's three b all the way to one Be all the way to eight b, but you don't look at that to determine the number of valence electrons. Let's take a look here. I've listed the outermost s orbital's and a deep orbital electrons for each of the transition metals. If we look at them, this is two plus one, which is three, two plus two, which is four, and it goes on and on. And then when we get to zinc, we see that it is two plus 10, which is 12. Remember, besides classified transition metals is Group B elements. If you look at a full, out electric periodic table that we did in later in earlier chapters, you'll see that these groups also have another set of numbers for their group identity. This would be Group three Group 10, 11 and 12. Remember our main group elements groups one a to eight a. But they also have another set of numbers that describe them. Group won a Group one group, Two Ways group, too. Group Three A is group 13 all the way to group 18 for Group eight A. OK, so just remember, if you're looking at the full out periodic table that I talked about in earlier chapters, you know that the transition metals are also represented as groups 3 to 12 and that new group number designation is also equal to the number of valence electrons. So just remember you could do with long way where you give the electron configurations of each transition metal and look at the number of total s and the electrons. Or you can just remember that the transition metals are represented as groups 3 to 12.

here. It says how maney valence electrons with, um, agonies five ion possess. So, um, agonies five means it has a five plus or plus five charge. That means that it has lost five electrons. So remember, man Goonies is a transition metal. It is in group seven of the periodic table. Don't confuse Group seven with Group seven A group 78 are the halogen. It's right. But here we're talking about group seven for this man. Manganese ion. So here from manganese, when it's neutral, it has seven valence electrons, but it just lost five. So we're gonna subtract out five, so it should have to valence electrons left. If you wanted to do with longer way to the use of the electron configuration, you could also do that. So here we need to find out what the electron configuration is of The neutral manganese it would be are gone for us to three d five. Now, remember, plus five means we would lose five electrons and we lose them from the high shell number first. So we lose to both of these electrons from for us, so they'd be completely gone, and we need to lose three Mawr to get to plus five charge. Those additional three would have to come from the three d set of Orbital's. So when we lose three more, we'd have left two electrons. Remember the number of valence electrons for transition metal is the S plus D orbital electrons. We lost our four s orbital electrons. So all we have left are these two D orbital electrons. So whether you do it the long way through the electron configuration or if you just simply remember, the secondary group number for the transition, metals is equal to their valence electrons. You'd also find out that you have to valence electrons left, so choose the way that you're most comfortable with to get your final answer.