hey guys hope you are well so now we're gonna start looking at chemical bonding you know your teacher's probably spoken about ionic bonding covalent bonding metallic bonding well that's what we're going to be talking about here and I'm quite excited to show you this because I've got some interesting ways of showing it which from my past of teaching lots of Learners in person I I was able to see that um they really understood this way of explaining this this topic okay so what I want us to do is I want us to remember that this is a periodic table and we've got metals and non-metals and we typically divide it by drawing the step that we've seen before so remember on the left hand side of that step so on the left hand side there we've got metals and on the right hand side these are uh okay I'm talking all before you write it there but on this side over here these are your non-metals okay and of course we must always remember that hydrogen is a little bit random hydrogen is actually a non-metal but for some reason we have placed it over there on the periodic table okay so what I want us to do now is I want us to take n a for example okay actually no we'll take we'll take lithium and I wanted to just go draw its basic structure so we know that it always has a nucleus okay and we know that a nucleus has protons and neutrons um so I'm just going to put a positive charge there because protons are positive neutrons are neutral so the overall charge of the nucleus is positive okay now this is for lithium so we've learned that lithium is now in row two so that means it has two energy levels going around the nucleus in the first energy level so in row number one um because to get to to get to lithium it's over here so you would first have to go there and there so that means in row number one there are two electrons so let's go draw two electrons in in um energy level number one then when you get to energy level number two um there's one electron so so there that is that those are the electrons in lithium and they are negative remember now the next thing I want us to draw is let's go to um n a which is sodium so we know that it's got a nucleus which is positively charged now n a is in row three so it's got three energy levels whoops so there's one two three now we know that N A has 11 protons and that means it has 11 electrons if it's a neutral a neutral in a with no charges and things like that so it's going to have 11 electrons Row one there would be two electrons that means two electrons in energy level one then in row two there's one two three four five six seven eight electrons but remember you always put down one at a time in the four different places okay and then once you've done that then you can go pair them up six seven eight there's the eight electrons that it has and then when you get to row three it's going to have one electron before we get to where it actually is on the periodic table and so if you have to go count all of the little black dots that would be 11 electrons okay and of course each of those are negative I'm not going to go through all the negatives now the goal now this this is the most important line that you could ever hear me say for bonding in grade 10. the goal of all chemistry the reason that these electrons are moving I mean these atoms are moving around and they're starting to bond with each other and to react with each other is to achieve a complete outer energy level that is the goal of all of these atoms that is what they are trying to do so I know you might be looking at them thinking Kevin what do you mean by that well I'm still going to explain that but right now this atom if you look at its outer energy level it is not complete how do I know that it's not it's not full with electrons so if lithium would like to have a complete outer energy level it has two options but only one of them is going to be correct and I'm going to show you that so here's lithium at the moment okay it's got one two and then it's got three electrons as we can see on the diagram now it would like to have a complete outer energy level this energy level on the outside is not complete so how could we make how could we make a complete energy level there's two options okay option one is going to look like this lithium if lithium would like to complete this energy level number two then in energy level number two they are one two three four five six seven eight blocks so that means to get all the way to having energy level number two complete they would have to be eight electrons on the outside so that means we'd have to add another seven electrons to lithium then it would look like that and then it's outside would be complete but this is not correct okay but let's just say it anyways um gain another seven electrons to complete energy level two so that's that's not the way it works in real life because that requires too much energy and if you understand how nature works it's based on energy how easy is it or difficult for something to happen so to be able to go and collect another seven electrons is extremely challenging for lithium to do it would rather do something else and now I'm going to show you option number two so option number two is that we don't go collect seven electrons like that that's going to be too difficult what we can rather do is what would happen if we just decide what would happen if this lithium atom just decides to rather get rid of this electron let's rather just give that one away so we could say here option two is rather get rid or let's say give the one electron away and that is so much easier to do rather giving one electron away instead of having to go collect seven okay because if it then does give if it does then give away that one electron then what would lithium look like well lithium would then look like this you would still have the nucleus in the middle whoops different color your nucleus would still be in the middle like that positively charged now it would only have one energy level because the outer energy level is completely empty so it's completely not even needed and then you would still have these two electrons that we can see over here and look at that it's complete because in energy level number one how many blocks are there to be able to complete it one two and so there are two electrons and so this lithium is super happy why because the goal of all chemistry is for an atom to have a complete outer energy level okay so remember that what did lithium do it rather lithium chose to give one electron away okay now we're going to quickly look at sodium trust me this lesson is going to get more interesting we're going to look at what these ones on the right hand side do it's going to get quite interesting so here's n a remember this was sodium okay and once again you need to decide what is it going to be better for sodium to do we can see that the the first energy level which has two is completed the second energy level which has eight is also completed okay so the inside the inside levels are complete but if you look on the outer level it only has one electron if it was to be complete it would have to have one two three four five six seven eight you would have to go all the way up to eight in order to complete it but we only have one now what is going to be easier to do so option one is that n a could go and collect another seven electrons because there if it's over here now and then it would go one two three four five six seven and then it reaches this last column which is where it's complete so it could go and collect or accept another seven electrons except seven electrons option two is that it rather decides to just give this electron away give one electron away so what do you think it would rather do well well then if you said option number two it is more easy for it to rather give one electron away so let's see n a what did it do give one electron away just like lithium did okay now we're going to start moving on to uh now we're going to go and draw magnesium oh no let's go draw uh beryllium and then we're going to look at boron carbon and nitrogen oxygen and fluorine we're gonna see what each one would decide to do and somewhere over here it's going to start getting very exciting and things are going to start things that your teacher said in class are going to start making a bit of sense okay it's going to really start coming together you'll see now okay so what we're going to go do now is we're going to go draw the just the structure of beryllium so we know that beryllium would have a nucleus which is positive and then because it's an in it it's in row two it's going to have two energy levels so energy level one and energy level number two now Let's Go full up what beryllium already has so beryllium has four protons and so that means four electrons if we assume that this is a normal neutral atom so it's got four electrons in energy level number one it's got one two electrons so we can go put two electrons over there and then for energy level number two it's going to have one two electrons so you always put them separate one two so that is what beryllium currently looks like okay so remember what is its goal the goal of all chemistry is to have a complete outer energy level so option one what could beryllium do guys what could go from here to here so it would go one two three four five six so it could gain it could go and gain six electrons option number two what could it rather do think about that carefully it could rather give away this one and this one so it could rather lose two electrons now the easiest one is going to be the one that requires the least amount of effort so it's easier to give away two than to go and collect six so this is what uh beryllium would do it would rather lose two electrons so beryllium would lose two electrons next we're going to look at Boron okay so we're going to look at Boron which is over here so Boron let's go draw its nucleus so we know that a nucleus is positive Boron is in row or period number two so it's going to have two energy levels so one and two okay now if you look at Boron it's going to have five electrons if it's just a normal neutral Boron so in row number one it's gonna have one two electrons just like we normally see and then in row number two it's going to have one two three electrons so one two three so the goal of all chemistry is for something to have a complete outer energy level so either Boron is going to try gain another one two three four five to reach this point over here so that would look like this would gain another five so it would go one two three four five and then you can see the outside is completely full the other option so let's just say that that's option number one option one is gain five electrons option two is that we rather just get rid of one two three electrons so just lose three electrons so look at that five and three so it's going to be easier to rather lose three electrons so Boron would rather lose three electrons let's just say here lose and lose you can say give or lose doesn't really matter we're now going to look at Carbon now here's where things are going to start getting interesting so let's look at Carbon now Okay so carbon has a nucleus of course which is positive well let's do it in red and that's positively charged carbon is in energy level number two what's in row two so it's got two energy levels in the first energy level it's going to have one two electrons and then an energy level number two it's going to have one two three four so we put them separate one two three four okay so now here's where things get super interesting carbon could either option one it could rather go this way and gain another one two three four electrons so it could gain another four so one two three four so that could be option one it could gain for but the other option is that it could lose four one two three four it could lose four electrons so what does it do in real life well it can do either it can go backward it could lose or game so for carbon it could gain or lose four electrons how cool is that okay now we're going to go on to now we're going to go on to nitrogen we're nearly done and then I'm going to show you something quite interesting so we're just going to go on to nitrogen now so nitrogen is um it has let me just see a seven electrons so I'm just going to take the carbon and I'm just going to add one more electron so this was carbon and then I'm just going to add one more electron so maybe like that okay so nitrogen is over here option one it could just gain another three electrons so it goes one two three so that's option one it could gain three electrons that would be one two three and then you can see the outer energy level is complete option number two is it could lose five one two three four five so it could lose five now that's not going to happen because five is more than three so it's actually going to choose option one where it's gonna gain three electrons so nitrogen is going to gain three electrons so can you see how when we started on the left hand side of the periodic table it was all about losing losing losing losing then we got to um then we got to started getting to this side and now we're starting to rather see gain or lose and now it's saying gain see so there's something interesting happening here how are we going to look at oxygen so oxygen has eight electrons so I'm just going to take the nitrogen and just add one more on the outside so it would have six on the outside because one two three four five six okay so I'm going to go a little bit faster now what would option one be option one B would that it just adds another two electrons so add two electron or gain two electrons let's stick with what we've been saying it could gain two electrons and then option two it could rather go and lose one two three four five six electrons it could lose six electrons now that's not going to happen that's too many so oxygen would rather gain two electrons and if it did that it would go like that okay and so now you could see that it has a complete outer energy level now we're going to quickly look at fluorine and then I'm gonna and then in a few in a few moments I'm gonna we're gonna do fluorine and then I'm gonna quickly show you these valency numbers that we used to look at um a few lessons ago and you're going to start understanding what those valency numbers are compared to what we've written down over here so let's go do fluorine so fluorine has nine electrons so it's got one more than oxygen so I'm just gonna quickly fix that up so that would be um it would have Harmony on the outside one two three four five six seven so uh six seven so that is what fluorine would do so option one it could just gain one electron so it could just gain one electron so there we go and then look it's complete option two option two is that it could rather give away all seven one two three four five six seven because then it would be complete as well so it could lose seven electrons but that's not going to happen that's too difficult to do so we're rather going to go with option one where it will gain one electron or let's just say a fluorine um gain one electron and then let's just quickly go do neon I just want to show you something these are called the noble gases and they do not react at all because they are already complete but let me show you why well let me show you how so if you look at neon it's got 10 electrons so on the outside it's going to have on the outside it'll have one two three four five six seven eight so on the outside it has eight so look at that neon neon is already complete on the outside it doesn't need to gain or lose any electrons so um neon did not gain or lose electrons and that is what noble gases are they are all of the elements in this period in this group of ear they don't react because they don't need to react because the only reason that things react is to be able to have an outer energy level okay so now we're going to make some interesting conclusions well first I wanted to show you something um we're going to look at valency numbers now if you were to go and do um this technique that we did in this lesson for um all of these in group one don't worry about hydrogen because hydrogen's in the wrong place but if you had to go to it for lithium in a or potassium you would see that all of them would rather lose one electron so I want you to think about this now if if an atom loses one electron will it become more positive or more negative it would become more positive it would become positive by one right because if you have if you have a nucleus that is positive and let's say you've got three let's say you've got three protons inside your nucleus and then you've got something like this and you've got three electrons one two three then what would the overall charge of this molecule be well it would be completely neutral or zero because it's got three positives and then it's got three negatives but we said that all of these in group one if they would like to become complete they would rather lose one electron so if they lose one electron then there are now three positives and two negatives so what would the overall charge become plus one so we say that these ones have a valency of plus one if you had to go look at anything in group two um such as beryllium they would rather lose two electrons after they lose two electrons they would rather become plus two when we looked at Boron we said that it would lose three electrons so it would become plus three but when we looked at Carbon we weren't sure if it should rather gain or lose four electrons so your teachers maybe told you that carbon is actually for its valency it'll be plus and minus 4. for nitrogen it would rather gain three electrons so if an element if an atom gains electrons it becomes more negative so it would become more it would become negative by three okay and then for oxygen it has to gain two electrons so it would become negative by two and then for fluorine if it had to gain electrons would gain one electron so it would become negative bar one because electrons are negative and so these are the valency numbers that you've seen before but now you have a better idea of what they actually are so the valency is an indication of what the atom charge will become when trying to complete the outer energy level okay and so that's really important that you understand all of this and then the last thing I just want to talk about and then we're going to end this lesson is that in general the metals now this is not a this is not like a it's not a 100 rule but it's something that you can remember the metals which are on the left hand side all of these guys and some of these ones over here if you look carefully what they like to do is they like to lose lose um they like to lose electrons so they like to or give away electrons Metals give away electrons and that's just because it's easier for them to give electrons away instead of trying to go and collect electrons okay and then what we noticed on this side was that the things on the side like n o and F they like to gain gain gain so they and they are the non-metals so the non-metals they like to gain electrons they like to gain electrons okay so that was a very uh information packed lesson I hope you got most of it and you understood most of the ideas I was trying to get across to you um in the next lesson we're going to take all of these ideas a little bit further thanks for watching