Isomers | Properties of carbon | Biology | Khan Academy

many times in chemistry will see different molecules that have the same constituent atoms for example these two molecules here they both have four carbons 1234 1234 so far right their chemical formula BCE for and then they both have 123 456 789 10 123 456 789 10 hydrogens so both love them both of them have the chemical formula c4 each 10 c4 h10 but they're still fundamentally different molecules and you can see that because they have different bonding for example over here we have a carbon that is bonded to three other carbon and hydrogen or rear can't find any carbon that's my 2 three other car but I can find one that about two two other carbons but not one that bond at three other carbons so how we've put the atoms together is actually different they're bonded two different things and so when we have the situation where you had the same constituent atoms we had the same chemical formula but you're still dealing with different different molecules because a either what their how their how their bonds are made or how they're what their shape is we call those isomers so isomer isomer you have the same chemical formula the chemical formula formula but you could have different bonding but different different bonding bonding or shape bonding shape or orientation corriente Asian so over here you have just different bonding in this type of isomers called a structural isomer so these characters are structural isomers team constituent atoms but different bonding structural isomers so that structural isomers right right over there now when you look at this pair this period the way those look like structural isomers only had the same constituent both of these for example have four carbons four carbons today both at 12 345 sick 123 for 5678 and they both have 8 hydrogens so we could both these are both see for each 8 a jade it looks like they're bonded similarly for example I mean though the left-hand side here these look identical on the right hand side you have a carbon bonded to another car been at that spot at three hundred and carbon bonded to another carbon responded to three hundred in Skyrim bonded to hydrogen carbon by did bonded to hire did so looks like the struck the the bonding that everything is bonded to the same things but you might notice a difference over here on the right hand side this ch3 is on the bottom right well over here to on the its on the top right and went okay well we know what's the big deal there these you know all these molecules are all moving around maybe they're rotating with respect to each other and these things could disk thing could have rotated down to become what we have appear if this was a single bond a Cinnabon would allow for that type of rotation it would allow for these things to rotate around each other for the think the model to rotate around that bond but a double bond it does not allow that rotation so this fixes these two things this fixes these two things in place and because of that these are actually two different molecules over here on the top you have the CH three groups they're both they're both on they're both I guess you could say facing down or the both on the same side love the double bond well over here they're on different sides they are on different sides the double bond and so this type love isomer -ism where you have the same positions and you know the same bonding this is called diário isomerism so we're here we're carrying much more about how things sit in three dimensions now we don't just care about what's bonded to water the constituents actually this one is we'll see this is also steer I summer because with this does carbon is bonded to the same things in either case so these are both these are both situations these are both sterio isomers sterio sterio isomers and this particular view creation to steer isomers called assist transacted summer sis is when you have the two groups on the same side sis and transit when you have the two groups on the opposite sides of the double bond sis trans isomers sis trends isomers isomers and these are often called a geometric isomers geo metric geometric isomers so that a subset so when I what's the strands are geometric I'm talking about these two characters a year they are a subset love sterio isomers now what's going on over you have no double bond I'm not talking about sis and trans a carbon as I just said is by the fluorine chlorine bromine and hydrogen chlorine bromine chlorine and hydrogen Howard these two things different and though the way that they're different is if you were actually tried to superimpose them on each other you'll see that it is impossible they are mirror images of each other because it's four different constituency you can actually not you cannot superimpose this molecule onto this molecule over here and actually because %uh that they actually have different chemical properties and so this over here these these two characters which is a subset sterio isomers cirrus rumors are concerned with how things are are are positioned in three dimensions not just there the how their body is different but this subset where you have these mirror images that cannot be superimposed we call these and then Shurmur's so these two characters these are financial MERS nan schumer's and an end show comes from Greek the Greek word or the recruit opposite so these are opposites of each other and they cannot be super oppose the mirror their mirror images so all these are different variations love isomers and once again you might okay these are clearly two different molecules I have different bonding but even sis trans isomers will have a different molecular will have different chemical properties these two in particular they aren't that different but they do have different chemical properties but sometimes they're so different that one might be able to exist in a biological system while the other is not one might be okay for your health and the other might not be okay for your help same thing for an answer MERS 1 might be biologically active in a certain way and the other one might not be about Jack Bauer biologically active in that same way