finally the color of a transition metal complex is also dependent on the lians involved so different lians are going to create Crystal Fields of different splitting strings so we can think of our D orbitals that are splitting into our higher energy orbitals EG and then our lower energy orbitals to TG of course being influenced by liance that are going to control how small or large the energy gap is and so for our ligans for example there's going to be two types that we are going to be f focus on we're going to have strong field lians and weak field liing so strong fi lians are going to lead to a large splitting energy so a larger Crystal fi splitting energy and weak fi lens are going to lead to a smaller Crystal fi splitting enery so the question becomes how do we start to organize ourselves and distinguish all this work guess what of course previous chemists have done it for us previous chemists have come up with the spec trochemical series which is what you see here and it will be given to you for exam so it's not something you do have to memorize but you want to be able to recognize it and of course use it in different problems so using water as our reference water is going to be seen as a weak fi um liing here now as you can see all of them here is all going to be considered weak fi and then you're going to have your strong fi Ling which are going to be from our NH3 all the way to our CN minus these are going to be all our Strong full light so now when you have a specific Lian whether it's weak or strong attached to a central metal ion now you can say okay well how large will this splitting be we can say okay is it going to be large or is it going to be small essentially we use the spectrochemical series for these Lian field strengths here to go ahead and predict the magnitude of our Delta amount of course in other courses you may actually be able to calculate this amount as well we not we will not be going into the calculation portion of also as our Crystal fi splitting energy increases higher energy light must be absorbed okay so if this entire thing gets larger with our stronger field liing that we see here then we must make sure that we are able to absorb the higher energy light so we're talking about our Blues our indigos and our violets when we're thinking of War vid and just to be clear we cannot predict the actual color of a given complex ion but we can determine whether um it will absorb long or short wavelength basically based on if it has an attachment to a strong field lion or a weak field lion and then of course we can use that to help figure out the compliment colors that it may absorb or transmit but for reference when it comes to questions you kind of want to make sure that you're organizing yourself so I always say just add a little bit of detail all of this if we run into a situation where say the lians are the same right lians are the same so you have to basically find a way to distinguish how these other particular properties can affect this um Crystal field energy here right so we're thinking of oxidation number if the liens are the same they're going to think of oxidation number and so we know if we have a higher oxidation number that's also going to um equal to a larger if the fill splitting also we can say that if we have a higher period as well so say we have two metals they have the same ligans they even have the same oxidation number well how do we distinguish them we have to think of the same period that they're in so say they're in period 4 which has 3D orbitals versus period five which has 4D orbitals we'll guess what um the 4D orbital are going to have um down the period they going to actually have a more positive nucleus which means they're going to want to attract the lians more and when they attract the liance more it means more repulsion so guess what more repulsion means more splitting which means a larger Crystal fi splitting energy okay and there's also several other factors that affect Crystal fi splitting that we do not go over like electro negativity the details of electro negativity from those potential polar bonds um Atomic distance size of lians all these little things as well but for now let's just focus on what we know and get into some examples to make better connections and start connecting everything as well okay all right so here are a couple questions and before we must start just remember we do have these flash card moments that means even in the previous videos you want to stop yourself in certain areas and make sure you're writing on a flash card a concept on the front and then something in your own words about that concept on the back to help you actively be a part of the lecture okay so we have these two examples here um the first thing we always want to do is just basically read the actual questions and start to point out any key terms that help us write notes about what we're doing so I'm just kind of reading this which of the following complex ions so I see complex ions want to pull that out absorbs light that's something we just learned about longest wavelength that's something we also learned about okay then it says rank um and then it says in terms of splitting energy or Crystal field splitting energy and the energy of visible light absorb so again we're talking about complex ions absorb light longest wavelength I know I have to relate oxidation number potentially I have to relate periods of the actual metal ions I might also have to relate Lian strength and so I'm going to bring out my um relative fi Lian strength that's here and then I kind of learned just be right in details for myself so for example um we know we can deal with ligans and they can be a strong filled or weak field and if they're strong filled they're going to have a larger Crystal fi splitting weak fied they're going to have a decreased Crystal fill splitting so what does it actually mean to have a larger Crystal fill splitting larger Crystal fill splitting means that they're going to have to absorb higher energy so you can also write absorb I like to just put everything like um like higher energy little AC or whatever and also weak fi they're going to absorb lower energy okay so absorb lower energy absorb higher energy okay we see that as well what else can we say about them if they're absorbing higher energy that means they're absorbing sh wavelength so high energy that means we're talking about short wavelength low energy we're talking about long wavelengths so here when they're talking about which are the following complex ions and we know complex ions are going to be a metal Lian that are charged just to add all those details where they're asking for are going to absorb light of the longest wavelength they're asking you and telling you that you want to focus on weak fi lians that are going to absorb light um that is low in energy with long wavelength so that means I want to focus on weak field liing so first I have to make sure that everything else is Consolidated you have to make sure that we have the same transition metals we're talking about or at least the same oxidation number so I'm going through and getting my oxidation numbers for this iron here so we have iron CL is a minus one so we have x - 6 which is equal to minus 3 so we're going to have fe3+ here we also have fe3+ here because we also have another minus one charge we also have fe3 Plus here we also have fe3+ here because the water is neutral and we also have fe3+ here so they all have the same oxidation they're all the same particular elements so they're all in the same period now we have to focus on ligans now we're focused on weak fi ligans so that means we need to be focus on water and anything over here if they're strong field get rid of them so we can get rid of this one we do not care about strong field now we need to focus on which one is the weakest because the weakest is going to tell us which one has the longest wavel we don't know the exacts but we can make a prediction of based on our spectrochemical Series right so we have the weakest being our iodine so our iodine is going to be letter e and so that is going to be the weakest which is going to be the longest wavel so that would be the answer for that one okay and that's pretty much what they wanted for that question here they want you to rank each of these three complexes in terms of Crystal field splitting and the energy of visible light absorb so when I think of ranking I mean I just think of ranking them from from the largest copil splitting to the smallest say Okay rank from largest to smallest okay we also got to get the oxidation numbers we still have TI here so we know that we're going to have ti3 plus here this is also neutral so we're going to have ti3 plus here this is going to be um this l in here is charged minus one so it's x - 6 is equal to 3 minus and so we also have ti3 plus here so all the oxidation states are the same now if you feel like wait a minute you're doing oxidation states too fast you need to go back and start reviewing those um examples more and just practice it more so that you're get more comfortable with them okay so our oxidation states are the same um they're all the same period now we have to focus on lians we want to rank them from largest to smallest so as you can see the strongest is going to be um the largest crystal fi splitting you already know that and so the strongest l in here is going to be RCN the next strongest is is going to be R NH3 and then the final one um which is the weakest here is going to be rh2o and so that's going to rank them from largest to smallest when it comes to Crystal fi splitting energy because of course the strong fi lians are going to have the largest crystal fi splitting energy and it also is going to rank them as far as the energy of visible light absorb because the stronger the ligan than the higher energy wavelength that they have the ability to absorb here okay so of course to answer this question fully we would just have to write down all of our complexes in this ring so this will be TI CN 6 3 minus then it will be TI NH3 6 3+ and then finally it'll be R TI H2O 6 3+ finally we can do another one here um with the same concept we want to focus on oxidation numbers we want to focus on on ligans want to focus on periods so let's go ahead and get our oxidation numbers we have cr here so this going to be CR 3+ we have Cobalt here CO3 plus we also have cr3+ here and we have ru3 plus so the oxidation States for each of them are pretty much the same yes they are different elements but for this one because they are all in period four then they're all going to pretty much behave the same whereas um Ru it is in period five so we do have to consolidate that so for example um our CR and they're going to be the same our Co they're all going to be um pretty much based on ligans but our Ru is in period five where all of these are in period four so that means if we do have to come down to distinguishing the one in period five is going to be the one with the larger cryophilic energy so they said arranging complex is in order of octahedral splitting energy they're starting off with the largest here and the smallest and so we have four of them so let's go ahead and rank these complex again we got our oxidations we see they're all very similar next we're going to go off of lians so we have strong fi lians and we have weak fi lians so um we have our spectrochemical series here we have F minus which we know is going to be weak filled we have weak and we have another weak we have strong and we have strong so we have some weaks and some strongs as we know because the oxidation States here are the same then we can just go based off a Lian these are definitely going to be um the weakest or the smallest splitting energy so we have to distinguish those two you say okay well if we know that they have both have the same oxidation state well how do we distinguish them whichever one has the weakest liing so we're looking at F and we're looking at H2 so we have F minus and H2 so that means our CR f63 minus is going to be the weakest after that the weakest is going to be Co H2O 6 3+ okay next we have these two that both have the CI CN minus Li which is very very strong so the only way to distinguish them is going to be by oxidation state or the period there in it you see they both have the same oxidation state so we have to go off of period CR is in period 4 which is a smaller period than period five so that means there's going to be more repulsion when you have a larger period like where you have Ru here so that means our Ru complex Ru cn6 3 minus is going to be the strongest complex and then we're going to have cr cn6 3 minus as our second strongest so the goal is to basically continue to make all the connections possible between Lian oxidation state and the course super period is in when you're trying to relate it to color or at least the ability for these lians to absorb certain colors based on that splitting energy in the D orbitals