we're gonna quickly cover chemical bonds. So you guys already know that chemical bonds air how individual atoms interact with one another and how they link and connect to other atoms. And really, chemical bonds fall under one of two categories either intra molecular bonds or inter molecular bonds. Now, intra molecular bonds are bonds that exist within a molecule, whereas inter molecular bonds exist between different molecules. And so these two words sound similar. And what helps me distinguish between them is that in trouble, molecular bonds are trapped within a molecule, whereas inter molecular bonds are not trapped, and instead they exist between different molecules. So, in our example below, we're gonna label the chemical bonds appropriately. And so notice we have two different HCL molecules down below. And this bond here between the H in the cl the chlorine atoms uh, this is trapped within the molecules, so this must be our intra molecular bond. Now, the other bond on shown here with a dotted line that exists between two different HCL molecules is not trapped. So this is an inter molecular bond, and, uh, in our next video, what we're gonna do is talk about specific intra molecular bonds, and that includes Ionic and Covalin Bonds. So I'll see you guys in that video
Ionic & Covalent Bonds
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So you guys already know that Ionic and Covalin bonds are types of intra molecular bonds that occur within a molecule and recall that ionic bonds are interactions between atoms that have opposite charges due to losing and gaining electrons but not sharing electrons. And recall that Covalin bonds occur when two atoms share a pair of electrons, and those electrons can either be shared equally or unequally. If the electrons are shared equally between two atoms, then this forms a non polar Covalin bond, a non polar covalin bond, whereas if the electrons are shared unequally than this forms a polar Covalin bond. And what determines the polarity of a bond is actually the difference in electro negativity electrode negativity between two atoms and so recall that electric negativity describes an Adam's affinity for electrons or how hard and Adam pulls on electrons. And so, in our example below, we're going to consider the three types of bonds. And in the Left column, we have Ionic bonds. So we know that Ionic bonds do not share electrons so we can put no in here, and in fact, what they do is they transfer electrons. So there's a transfer of electrons, but no sharing now. Covalin bonds regardless of the type, we know that there is sharing of electrons so we can put yes in here. Now for polar Covalin bonds. We know that there is unequal sharing of electrons, whereas for non polar Covalin bonds, we know that there is equal. There's equal sharing of electrons now for the electro negativity of the atoms and Ionic bonds. The atoms differ greatly in electro negativity, and there's actually a transfer of the electrons now for polar Covalin bonds. There's also a significant difference in the electro negativity between two atoms, but there's no transfer of electrons. They're still sharing the electrons. And in non polar Covalin bonds, theater ums have either the same electro negativity or a very, very similar electro negativity. And so, for examples, recall that the classic example of an Ionic bond is table salt or sodium chloride, where the sodium has one less electron and the chlorine has one additional electron than proton, and so that gives them their charges. And the the opposite charges is what keeps this molecule, uh, intact or allows them to create an ionic bone. Now, over here for polar, we know that water molecules are polar molecules because they have a new oxygen and hydrogen oxygen zehr super electro negative. Whereas hydrogen are not electro negative, not very electro negative. And so Oxygen's are gonna have a partial negative charge and the hydrogen zehr gonna have a partial positive charge, and that will occur on both hydrogen. And over here with this molecule, the carbon dioxide. There's also polar bonds so you can see the carbon here is gonna have a partial positive charge, whereas the two oxygen's air gonna have partial negative charges. But because the polarity is going in opposite directions, So you have electron density being pulled in opposite directions, the overall molecule, Even though it contains polar covalin bonds, the overall molecule is non polar. So for a molecule to be considered polar, you also have to consider its shape. And so this is a non polar molecule that contains polar bonds and then for non polar Covalin bonds. We have this hydrogen gas molecule where we have two hydrogen atoms that have the same electro negativity. And so that creates a non polar bond where they share electrons equally. So in our next video, we're gonna recap inter molecular bonds. So I'll see you guys in that video
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so recall that non co violent inter molecular forces includes hydrogen bonds, dipole dipole interactions and Vander Wal's forces. So recall the hydrogen bonds are interactions that involve ah hydrogen atom as well as electro negative atoms such as nitrogen, oxygen or flooring. Now a die pole itself simply explains a shift in the electron density that results due to electro negativity differences between two atoms. So if you have a die poll on one molecule where there's an electron density shift and then you have another die poll on a different molecule that can create a dipole dipole interaction between the two molecules. And so that's what we see here now, Vander Waals forces are forces that exists between all molecules because it results from instantaneous die poles that can exist at any moment in any molecule so down below. In our example, we're going to label each of these diagrams with the appropriate inter molecular force. And so here with these Carbonnel groups on these different molecules, noticed that there is a dye poll moment going in this direction towards the oxygen in both molecules to create a partial negative charge on the oxygen's and a partial positive charge on the carbons. And so there's an attraction or an interaction between the partial positive carbon here and the partial negative oxygen on separate molecules. And so that is our dipole dipole interaction. Now, over here on the right, we have water molecules, which we know are also polar molecules and have their die poles. And so each of these oxygen's is partially negative, and each of the hydrogen is partially positive. And so, uh, that applies toe all of these water molecules. And so there's going to be specific type of dipole dipole interaction called a hydrogen bond between the hydrogen atoms on one molecule and the oxygen atoms on a different molecule. And so that is what a hydrogen bond is. And so notice that a single water molecule here conform up to four hydrogen bonds. So here we will put hydrogen bonds. Now, for our last example, we have these two non polar molecules, these two non polar hydrogen gas molecules, and so overall they don't have any partial charges because they have a similar electro negativity and there's no shift in electron density. There's no die polls, However, at any single instant there could actually be an instantaneous die poll where one of these hydrogen could have a partial negative and the other could have a partial positive at any instant. And so at that instant there would be an attractive force between the two molecules that are non polar. And so this is where our Vander wal's come into play that exists between all molecules and so this is a good summary of our inner molecular forces, and I'll see you guys in our practice videos.
Which of the following is classified as a nonpolar molecule?
Identify the types of chemical bonds present in scenarios #1 & 2 below: