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Ionic and Covalent Bonding - Chemistry

Jun 02, 2021
Consider this problem, what kind of bonds are contained in the following substances? Is it

ionic

or

covalent

? If it is

covalent

, would you describe it as polar covalent or nonpolar covalent? Now, before we tackle this problem, we need to be able to determine the difference between an

ionic

bond and a covalent bond, so how can we quickly tell the two apart? Let's say if we are given a test problem. The first thing I recommend knowing is that an ionic bond is usually between a metal and a non-metal. Covalent bonds generally exist between two non-metals and within an ionic bond an ionic bond occurs between ions and ions are particles that contain positive and negative charges covalent bonds basically have partial charges if it is polar covalent if it is nonpolar covalent then those charges are minimal now the second thing you want to keep in mind is that covalent bonds involve sharing of electrons whereas ionic bonds are created by a transfer of electrons and later in this video o I'm going to explain these concepts but let's see if we have enough information to answer this particular question so let's understand part a or answer br2 what kind of bonds does that substance contain then br2 is bromine and it looks like this then you have a molecule that is made up of multiple atoms in this case this molecule has two atoms and within this molecule you have a single bond and each atom has three lone pairs this is what the bromine molecule looks like but now let's describe the bond what holds these two atoms together is it ionic or covalent so do we have two non-metals or is it a metal mixed with a non-metal?
ionic and covalent bonding   chemistry
Well, you need to know where the metals and non-metals are located on the periodic table to answer that question in the first one. let's take a minute and talk about that so if you go and get your periodic table or if you don't have one go to Google Images and search for the following elements they should be in the top right hand side of the periodic table and you're going to see this line which divides some of these elements now most of the elements located near that line are known as metalloids or semiconductors a metalloid has properties that are between a metal and a non-metal but what you want to take from this is that the non-metals are located to the right of that line and to the left of that line you have the metals, so by using the periodic table you can quickly determine if an element is considered a metal, a nonmetal, or if it's on a line, a metalloid, so that bromine is on the right hand side of the periodic table therefore bromine is considered a nonmetal so here we have two nonmetals mixed together and because those elements are the same the two electrons that are in this bond they will be shared equally between those two atoms so we are going to have a covalent bond so anytime there is some kind of sharing of electrons you have a covalent bond now that we have a covalent bond we need to discuss if it is a bond polar covalent. and or is a nonpolar covalent bond in a nonpolar covalent bond the electrons are shared equally if it is polar covalent that means the electrons are shared between the two atoms but relatively unequally so in this case this is going to be a nonpolar covalent bond because the elements are the same for it to be a polar covalent bond the elements have to be different so let me give you some notes on this so if it's going to be polar covalent the electronegativity difference has to be 0.5 or more a nonpolar covalent bond has an electronegativity difference value of 0.4 or less so keep that in mind now let's consider methane ch4 here is the lewis structure of methane and off we go focus on the hydrogen bond of carbon so this particular bond is is it ionic or is it covalent what would you say and let's compare that bond to the bond between two hydrogen atoms now automatically if the ele elements are the same in a chemical bond so you know it's going to be a non-polar covalent bond but if the elements are different it could be ionic or it could be polar covalent or it could even be non-polar covalent but first let's see if it is ionic or covalent then the is carbon a metal or is it a non-metal What would you say carbon is considered a non-metal?
ionic and covalent bonding   chemistry

More Interesting Facts About,

ionic and covalent bonding chemistry...

It's on the right side of that line. Hydrogen though is on the left side. It is not actually considered a metal. It is considered a non-metal, so be careful with that. one here we have two non-metals combined so we know this is a covalent bond now is it polar covalent or is it nonpolar covalent answer that because the atoms in that bond are different we need to look at the electronegativity values ​​here are some common values ​​with which you want to be familiar the electronegativity value for hydrogen is 2.1 for boron is 2.0 for carbon 2.5 nitrogen is 3.0 and then oxygen is 3.5 fluorine is 4.0 is the highest and then we have chlorine which is 3.0 bromine 2.8 iodine 2.5 and you can look up these values ​​if you go to google images and type in the electronegativity values ​​it should show up so in the ch link the electronegativity difference between the two elements is 2.5 minus 2.1 which is 0.4 so that the bond is considered nonpolar if the elements are the same then the difference will be zero which means it is definitely nonpolar so both bonds are coval bonds non-polar entities, now let's move on to part c, so what kind of bond do we have between the elements carbon and oxygen? lets say is it ionic or is it covalent well carbon is a non metal and oxygen is a non metal so we have two non metals which means the bond between them is covalent instead of ionic now to determine if it is polar or non-polar, we must observe the electronegativity values ​​carbon has a value of 2.5 and oxygen is 3.5, so the difference in electronegativity between the two elements is 1.0, which is greater than 25 so this particular bond is a polar covale nt bond and that's basically how you can quickly tell if it's polar covalent or nonpolar covalent and that's by looking at the difference values ​​in now let's move on to lithium fluoride is it ionic or covalent?
ionic and covalent bonding   chemistry
Well, lithium is on the left. side of the periodic table so it's a metal actually it's an alkali metal fluorine is on the right hand side of the table it's a halogen which is a type of nonmetal and here we have a metal and a non-metal when you see that tells you that you are dealing with an ionic bond now let's dig into ionic and covalent bonds let's understand how they are formed now let's start with ionic bonds before we go back to covalent bonds lithium as an atom has one valence electron fluorine as an atom has seven valence electrons fluorine as a non-metal has a very high electronegativity value it's 4.0 and lithium as a metal has a very low electronegativity value I don't remember what the number is but it could be like 1.0 or less but it's pretty low w and because fluorine is more electronegative it has a strong affinity for electrons it really wants it and halogens like to have eight electrons to satisfy the octet requirement.
ionic and covalent bonding   chemistry
What you have to understand is that metals like to give up electrons and non-metals like to take them away, so what's going to happen here is we're going to have a transfer of electrons, so lithium is going to give up, it's a electron to fluorine. and so when lithium loses that electron it will take on a positive charge, when fluorine gains that electron it takes on a negative charge, now what do you know about opposite charges? If it has a positive charge next to it, let's say a negative charge, what will the two be? do it right opposite charges attract then you will have a force of attraction and this force holds them together so this is the chemical bond between these two ions it is called ionic bond so that electrostatic force of attraction is what holds them together ionic bonds now let's consider the situation in a covalent bond and use bromine as an example so bromine as an atom has seven valence electrons like fluorine and because they are in the same set of seven a columns of the periodic table they both they're halogens and as a result they both want eight electrons when a bromine atom meets, say, another bromine atom they both want to have eight electrons but neither wants to give up their electrons and they're like how are we going to resolve the situation?
I need an extra electron and you need an extra electron. What kind of deal can we make so that we both get what we want? In this case, what they do is share. electrons and bromine gives up an electron to form a bond and the other bromine atom also gives up an electron and note that it takes two electrons to form a bond and so we get the bromine molecule which looks like this and the There is a single bond between them, so each bromine atom now has eight electrons around it, so if we look at the bromine atom on the left, two, four, six and this is considered two, so that's eight electrons, which The same is true for the one on the right. it has two, four, six and both shared electrons, so it has eight and in this arrangement they satisfy the octet requirement that they have, that is, having eight electrons in their outermost energy level now because the electronegativity of the two atoms in this molecule it is the same the electrons are shared equally so this will be a non polar covalent bond now let's talk about the other situation a polar covalent bond and in this video we use the example of carbon and oxygen so that carbon as an atom has four valence electrons, oxygen as an atom has six valence electrons, now they are both non-metals and as a result they want to acquire electrons, so as in the example above, they need to make a deal, they need to share electrons so that both of them can have eight the question is how are they going to do it in this case they are going to share electrons unequally for this to work carbon is going to give up two electrons to make a bond between carbon and oxygen but oxygen is going to give up four electrons and so we have a total of six shared electrons and if you remember it takes two shared electrons to make a bond so six electrons will make a triple bond, the Lewis structure between carbon and oxygen looks like this, so those are the six electrons that were used to make that bond, so carbon gave up two, meaning it has two electrons left.
Oxygen gave up four, which means it has two left too, and this is the Lewis structure for carbon monoxide. Carbon has an electronegativity value of 2.5. and for oxygen it's 3.5 and because oxygen is more electronegative than carbon it will pull the electrons in that bond closer to itself so the oxygen will take on a partial negative charge and so it has this search symbol delta for partial charges and uh carbon because it has a lower electronegativity value relative to oxygen it will lose some electrons to oxygen oxygen will pull those electrons closer to itself they both still share electrons but what we have is unequal exchange of electrons and because of this unequal exchange, one element pulls on electrons more than the other and because oxygen has a higher attraction it will have a partial negative charge while carbon will have a partial positive charge and when you have these charges partials in a covalent bond makes it a polar covalent bond when something is polar it means it is still neutral overall but is polarized a la do has a partial positive charge and the other side has a partial negative charge and that's what it means for something that gets polarized you have a separation of charges on something that is intrinsically neutral because in general this is a neutral molecule if you add plus or ne and a negative one you get 0. but you have a variety of partial charges within this single molecule so this is a polar covalent bond so what I'm going to do now is summarize what we just considered so that we can talk about ionic bonds and we talk about covalent bonds now within a covalent bond it can have two types it can be a polar covalent bond or it can have a nonpolar covalent bond so for the ionic bond we have the example of lithium fluoride now in an ionic bond has ions lithium has a positive charge fluorine has a negative charge in a polar covalent bond we had molecules like carbon monoxide however we didn't have we had a full charge but we had a partial charge carbon was partly positive and oxygen was partly negative so make sure you look at the difference in ionic bonds you have full charges as plus one or minus one whereas in a polar covalent bond you can have partial charges, they could be 0.1.2 but it is not a full charge in a nonpolar covalent bond as in In the case of the bromine molecule, the electrons in this molecule were shared equally, so there are no partial charges and If you remember, ionic bonds are usually made of metals and nonmetals, while covalent bonds are usually made of two nonmetals, either polar, covalent, or nonpolar. covalent and remember that the difference in for a polar covalent bond has to be 0.5 or more for a nonpolar covalent bond it is usually 0.4 or less soso that's basically it for this video which is a summary sheet of what i have and there's one more thing i want to mention ammonium nitrate.
This is one of those exceptions that you should be aware of. Would you consider it to be ionic or covalent? Now, looking at the elements nitrogen, hydrogen, and oxygen, you'll probably notice that there are no metals in this example, so you might be thinking that this is a situation between two nonmetals, but it's not, you can't rule out ionic bonds in this case. because it turns out that this compound has a mixture of i ionic and covalent bonds, ammonium is a positively charged polyatomic ion and nitrate is a negatively charged polyatomic ion, so between the ammonium ion and nitrate ion have an ionic bond even though there are no metals so this is one of those exceptions where you have an ionic bond between two non-metals so when you see a metal and a non-metal it's normally an ionic bond if you see two the nonmetals usually is a covalent bond but it could be an exception as you can see in this case now for this particular substance ammonium nitrate we have covalent bonds within the polyatomic ion so within the ion ammonium that looks like this, the bond between hydrogen and nitrogen is a covalent bond it is a polar covalent bond the difference ian is more than 0.5 the electronegativity value for nitrogen is 3.0 for hydrogen 2.1 and for the nitrate ion that is you see like this we have another polar covalent bond between the nitrogen and the oxygen the difference is 0.5 so within this molecule you have ionic bonds and covalent bonds so there are exceptions you need to be aware of but the things that were mentioned in this video are general rules to keep in mind

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