Mr Carlson the Science Guy for Lesson Four in unit 2 uh we're going to be talking about Cove valent bonds so when we're looking at different atoms that um that are wanting to come together to form molecules uh one of the types of bonds that we'll see are Cove valent bonds um so let's take a look at some examples so in this example we have two hydrogen atoms um we have a proton in the nucleus giving a a positive charge and the electron on the First Energy uh electron energy level uh having a negative charge so when we put two hydrogen atoms next to each other what happens is um the negative charge uh from the the electron on one atom has an attraction to the positive uh charge in the center of the the atom in the nucleus there due to the the proton there and so remember opposite charges uh attract and so uh they they have this inclination to come together or they want to be near each other and the same thing happens with the other electron on the opposite side um that has a a connection or an attraction to to the the proton there and so it's being pulled together and so in this final step here um what happens is these two electrons here are end up they end up being shared by each of the atoms and that's important to to understand because in the first energy level uh the maximum number of electrons that fill that first energy level so for example if we have a nucleus and then we have have an energy level there and an energy level here remember the the the number that fills that first energy level is two electrons two electrons with a negative charge and so both of these hydrogen atoms want both of those electrons in their outer shell because remember uh atoms want to be stable and stable is all about having um the maximum number of of electrons in your outer shell when you don't have a maximum number you have this these atoms have this desire to go and grab one from another atom nearby and so when it can grab an uh sorry when it can grab an electron from an atom nearby um it's happy and so in this situation uh this atom here has those two and so um it's stable it's happy um but it can't just take those electrons from the other atom it has to share them because the other atom also wants those two uh electrons because it also wants to be stable it wants to fill uh that outer energy or sorry that first electron energy level uh it's actually the only energy level there because um there's only uh two electrons there and so when they're both able to share uh they're both and So Co valent bonds are all about atoms sharing electrons so let's take a look at another example so in this situation we have three different atoms we have those the two hydrogen atoms we just worked with but then we're bringing in this oxygen atom and so remember when when we uh consider chemical bonds bonds between atoms the focus is really uh the focus is on the the uh veence electrons on the on the outer energy level here and so if we we we sort of ignore nonvalence electrons when we're talking about bonding because the the important ones are the ones on the outside and so what do we have here we have a hydrogen uh atom that only has one electron in its first shell that can hold two so it really wants an electron I'm just going to write e with a negative charge there to me since electrons have a negative charge uh let just kind of shorten the shorten the the writing there um this one also wants an electron to fill its its energy level and then we have oxygen so let's switch to a different color here so oxygen has six electrons in the second energy level right it's filled up its first energy level there so the any more electrons uh are going to go into the second energy level the second energy level can hold eight electrons and so we have 1 2 3 4 5 6 and so you maybe your brain is starting to to see where it's going to get them right so in order to reach that eight which makes it stable right which makes it happy uh that the oxygen is going to um sort of pull in these two electrons from the two hydrogen atoms and it's going to come together to to share electrons that way the hydrogen is Happy the other hydrogen is happy and the oxygen is happy so let's move over right so we have this attraction here um where where each each electron is sort of being uh wanting to be pulled to a particular atom the other electron wants to be pulled to the other one right and so you get this this desire to be shared this desire to be um Cove valent bonded and so this is the end result when we share the electrons um this hydrogen atom has two in its only shell so it's happy um this one has two in its outer shell it's happy and then the oxygen has eight um and then that makes it happy as well and so what this ends up being is uh a simple water molecule uh two hydrogen and one oxygen atom U with uh two bonds right there and right there okay so the bonds uh let's go two bonds there um to make each of those atoms uh happy with that situation and then let's take a look at one more example down here and so in this situation we have two oxygen uh so six veence electrons on the outer uh the outer shell um so in order for these uh these two atoms to uh reach stability they're going to sort of they're going to share with each other um and so what happens is uh you get uh one of these electrons uh wants to be pulled over here but then you also get a second pull right because there's only one atom here uh we can't pull one electron from a variety of atoms what happens is uh they want to pull each each atom wants to pull two electrons from the other one and so we get this unique situation here where we have what's called a double bond and a double bond is is unique but again it all stems from the desire uh for each atom to be stable it wants the outer shell and when I say outer shell I mean the energy level so when I say outer shell that's another way of just talking about electron energy level same thing um so it wants them to be full so in in each of these situations uh the outer electron energy level has eight so 1 2 3 4 5 6 7 8 and then this one as well and so it only accomplishes uh reaching stability when they when they share when they have two uh bonds that they're sharing in this situation and so in this situation once these Bond what we we are left with is an O2 molecule okay so we call that uh actually just a little extra information we call this a diatomic datomic uh molecule uh because uh there are uh two um we call this a diatomic atom oxygen because it really has it never wants to be left alone so inevitably you find oxygen bonded with another oxygen in the environment and we call it diatomic because there are generally uh two di meaning two uh two atoms bonded together in nature uh so you won't really see single oxygen uh atoms existing in nature for the most part okay so calent bonds are sharing and we share uh in order to reach stability which is when our outer shell is uh reach reaches its maximum number based on how many it can hold all right that was lesson 4.4