a [Music] [Music] good morning everybody today we'll be starting on another chapter which is D and if block elements so what are these elements particularly we should know and what are those positions and another name of these block elements are transition elements so one important definition for this is transition so these are transition elements and if we consider their position in the periodic table they run from group three to group 11 in the D Block so we all know that when we start from left hand side of the periodic table we find that group one and group two elements are there and at some point of time we'll find that group three and up to group 11 will come and these transition elements and if they are present from the occupancy in the D cell then we consider them as elements of d block so we'll just go up to group 11 so what about group 12 so if we ask somebody that what are the group 12 elements give some example of these group 12 elements we know immediately some can say that we have jinc cadmium and Mercury so that question immediately comes to ask that whether we should include group 12 Within These or not that we'll discuss let later on so what about these that the definition of transition what is the transition because of their position so in the periodic table they present in between a block and the P block element so their position in the periodic table is important in the periodic table and it is is between here we have the S block elements and on the right hand side we have the P block elements so positioning of these elements therefore are important and this position is the transition position from s to P so if these are s and these are P elements or P block elements so we basically move or go for a transition from s to P via these element so that's why these are known as transition elements and in terms of their properties we'll find that the properties are also transitional these properties are also transitional from s to P so what is the transitional property that means these property properties will be in between s block elements and the P block elements so they are first thing what we consider is their metallic properties so what are the metallic properties of A and P block elements like sodium potassium magnesium and calcium we know that they are they are corresponding metallic in nature so when we move from them to these elements we'll find that they are also so highly reactive metallic elements so so if we move from these so Swit is also very much similar to that of your s block elements so they also form like s block elements as we slightly moved from s to this they will also form typically ionic compounds and we know that the elements on the right hand side including the halogens they form the corresponding elements in the P block but these P block elements are largely equalent so they will get some property inherited from these P block elements also and in some cases in the latter part of the periodic table on the right hand side of these d block elements they will also form some calent correctors something related to these P block elements so as we know so s block property is also there so some amount of P block property like elements of P block as it gives typically or largely calent compounds so some of these transition elements also will be responsible for giving typically all of these calent character to this particular Series so so what we'll find now that many of these properties so these two properties we mostly consider which are the physical properties so how we can consider that means physical properties of these elements and the chemical properties since we are considering their properties in relation to S block and P block elements and what we are doing we are doing doing in these blocks that we are adding electrons not on the ultimate or the outermost cell but is the penultimate cell is responsible so we have the penultimate cell and the cell is also expanded when we know that s is filled and P is filled we get eight electrons but in this case the D level is filled D cell is filed so we move from 8 to 18 electron occupancy as a result many of these physical and chemical properties of these Metals when you consider these as the metals so you they have the metallic property so metals of these group such as nickel such as copper so what are these Metals so they will have some properties which are in common and they give rise to something which is typically the metallic property that means they are good conductors such as for both these two things that mean they are good conductors for electricity and heat then they can have metallic cluster they are also hard and strong because when we talk in terms of the metallurgical behavior of some of these metal such as iron iron also comes into this category as the transition element of the D Block element how we can improve that uh the property which is strong related to the metallic property and in some cases they are also ductile and another property which is very much related to their physical property is that they also form Alloys Alloys with other metals so these group of elements how we can therefore Define so we just go for now the definition because the definition will consider all the species which will be there and we'll have if we have the Del electron configuration so the Del electron configuration whether the Del electron configuration can have connection with this definition of these transition elements so that we see from here that this not only the D but also will'll be considering the F block elements in a similar fashion in the L part of this chapter we we'll first find what are those a block elements so before that we'll just consider what are these D elements and what are the transition metal ions so by definition a transition metal is an element whose atom has partially filled d sub cell so the occupancy of this d sub cell is important and which can give rise to CES with an incomplete d sub cell so if it can give rise to some cations which have incompletely filled d sub cell then that particular metal or that particular element we consider as the D Block element so we have the incompletely filled D orbitals so if we have the D cell or the D orbitals then what we'll find that these are all incompletely filled and where these incompletely filled D orbitals or D cell in its ground state or in any one of its oxidation states which is therefore important that the ground state configuration should give us an incly fill D Cel or any of its oxidation state so when we'll consider their possibility of the oxidation States whether it has a one permanent or one very easily accessible oxidation state or it can have the different oxidation state whatever oxidation state you can have whether you have a incompletely filled D cell or not that will typically define whether you're are talking about the corresponding element which is a ition element such that the most common practice we know from early days of our schooling that iron is there we know that iron can have 2 plus or iron can have 3 plus so one we consider as a common name as the feros I another is known as the feric iion so any of its ground States basically that means whether it is present in the ferah state or feric state we we can have incompletely filled D level or the D cell or the D orbitals which will typically define whether our this Fe 2+ or fe3+ both of them can be considered as the corresponding transition element derive derived ions so these are all transition ions or transition element ions which can be dered from Iron which is F0 so in a similar way we basically give for the definition for a block and in these two cases we just considered that since the group will start now because you here we follow that the transition elements are falling from periodic T after calcium similarly here these are starting from lanthanum and actinium so where the position of this lanthanum and the position of the actinium we should know and based on that we basically considered that following that so once the lanam we reach then the following electron configuration or the occupancy in the cell which is whether D or F is different and this occupancy will considered as again some type of transition metals but this type the occupancy is not D but it could be occupancy of the F cell so occupancy for the F cell will basically give us something where we can have a group of elements or group of metals which will consider as inner transition elements because after d we just get again not a ultimate cell but it is a penultimate cell below this three D level is the inner transition metals or inner transition metal lines so initially if we just simply consider a part of the whole periodic table which belongs to the D Block elements and those DB block elements are very important to understand that means on the left hand side we have till calcium which has atomic number of 20 and on the right hand side we have the ple elements so in between we have in the period three so we have period one period two and period three after when we reach period three then only the possibility of coming the corresponding d c is there so after calcium we'll be having the element first element will be Scandium so then we have the Scandium titanium vadium chromium manganese iron Cobalt nickel copper and jinc so already we have defined this we are excluding these that means Jin cadmium Mar from this list because these are group 12 elements and we cannot consider by that particular definition that means the completely filled D Cel which cannot be applied to jinc in its ground state or jinc in its typically available or most commonly available oxidation state which is jinc 2+ so we'll just get for period four which is scandium to copper and what are those electronic configuration that will follow that these are occupying 3D levels so these are also 3D elements or 3D block elements starting from Scandium to Copper similarly if we go the next period which is period five we get itum to zarconi navium to ultimately to Silver and cadmium and similarly period six will give you something where we have you see that 57 to 71 these are by definition these are the a block elements and after that a block element then only we'll get the electron occupancy or electron filling to the D level which is hnum then tantalum then tungen to ultimately to Gold so these three we mostly or commonly encounter so this particular group that means from Scandium to Gold 79 we see that if we just be in the group level also the group similarity will also be there so all all these we considered as the Triad because these are not naturally occurring elements for the period 7 only some synthetically prepared elements have been accumulated over there and day by day we are just filling up all these levels already we have filled up all these levels till this uh 111 atomic number but these three periods particularly period 4 period 5 and period 6 are very important to study these things and we know that one particular that means the clubbing of all these elements we put together that means the three D elements or 3D block elements or DB block elements for Scandium to Copper we see that how their properties are changing as we move from Scandium to Titanium to vadium to Nickel to Copper similarly as we move from this particular period 4 to period 5 to period 6 what is changing we are just changing from 3D to 4D to 5D elements so down the group that means group four elements group five elements group six elements and group seven elements and group eight elements so down the group how the properties of all these groups can change because the ultimate electronic configuration will be same such as that of our nickel which is group 10 element and of 3D and of 4D it will be padium and for 5D it will be platinum so if we just consider something that means initially we have we don't know much because we are not very much concerned about the corresponding chemistry of the metallic part because it's relation to the metaller and the metallic part or the alloy formation but if we take out those two electrons that means two s electrons on the left hand side so s electrons will be losing first so we are remaining with the D electrons for its katonic form which is ni2 plus so if we have ni2 plus from here similarly if we can have padium 2+ or if we can Platinum 2 plus in all these cases we'll see that the corresponding configuration in terms of the occupancy in the D level will be 3D some number there 4D some number and then 5D some number similarly these properties that means from Iron ranium and osmium but interesting thing is that as we move down from Iron to ranium to osmium and the size of the D Cel or size of the D orbitals are increasing enormously and the corresponding properties and the reactivity patterns are also changing so the next thing what we'll be seeing that how we can consider that what should be the electronic configuration of say Scandium 21 or say Platinum 78 we should have some good idea how quickly we can write that it has the ultimate electronic configuration for Scandium Scandium Z is 4s2 3d1 that means the first electron is entering in the level which is 3D and that means that we have the unoccupied 3D level so Scandium by definition falls under that category of trans element so titanium will be in the similar way that means the 4 S2 3d2 so what we are getting starting from group 3 to group 11 we are getting D1 D2 D3 D4 D5 D6 D7 d8 and D9 system so another way of classifying or placing all these in the periodic table is important s that we quickly consider that in a particular oxidation state we can have electron configuration which is also known by its positioning in the corresponding group so what we see that in the long form of the periodic table that means the color which will be telling us that the pink color will be telling us that these are the transition metals so Scandium to corresponding gold so this group this group and the left hand side we have the corresponding s block elements and the right hand side we have the P block elements in this side and then the uh Group which is iner also we know and as we move from here that means after lanam we'll be getting the corresponding occupancy like that 10 electrons in this particular group similarly we have 14 electrons in the F level so after lanam we get the series from here to here that means serium to leasum these are known as lanthanides similarly after actinium whatever element that means the 14 elements will be pushing there due to the occupancy of the corresponding 5f level are known as correspondingly actinides so these two groups will be coming over here before that we should finish our discussion in relation to the corresponding transition elements and mostly we always concern about the particular part which which is the first transition series because we know very much because these are mostly commonly available on the earth crust because as minerals and or the corresponding abundances are more even they have present in the biological form in the biological system Even in our body because iron we all know Iron is present in our body also and a particular process like the process we call is a mineralization process that mineralization process is responsible for storing iron on the earth crust similarly other process which we can consider in a similar way that is the biomineralization process and that biomineralization process can be considered for storing iron in our body also for the synthesis of hemoglobin and myoglobin like things so these elements are so important that we should know very much because they have different interesting properties related to the transition elements so the definition is that for pink element that we have partly field D levels and for these two groups for lanthanides and actinides we have the partly filled F cells so if we just consider that what about the period four transition metals so we'll be just knowing now that what are those metals because we quickly will see that a particular type of metals what we'll see that we can have these corresponding properties of these Metals particularly how we can store and just now I'm giving some examples that iron we know that iron in a metallic form we know that iron nail we know iron nail or iron seat we know so use of iron we all know very much similarly if we get some something that the corresponding ions fe2+ and fe3+ and if I now say that any of them is also present in our blood as hemoglobin and myoglobin so this particular thing will concern about the corresponding transition metal these are not Metals so the corresponding property of these thing is that we have the corresponding property of this and how this iron will look like some of us have some good information about what the iron nail will look like iron seat will look like but what are these particular things will be in solution so whe this whether this will be soluble in water medium or any other medium and how they will also look like and similarly some of these elements can also be useful for the alloy formation so before going into that particular detail because iron but we know that iron is also present from the ore and minerals because this will all be present on the earth crust and if they are present as some oxide and in all of our redox classes then in the previous classes we have identified that how we can recover iron Elemental iron or the metallic iron from all these ORS so this is a typical process which environment does for us the Earth is doing for us and we are storing that particular one and when you recover so recovery process is typically the corresponding metallurgical process so this is the corresponding metery we can have and that giving rise to the IR zero but how this iron basically iron will look like suppose if you are given with some iron powder because it has some important property for this iron as a dust particle type of thing so how this iron powder will look like so only some examples for this period four transition metal the first one is a typical example for Scandium this is the metallic Scandium so metallic Scandium is there which is the c oning group the element and if we put that on a petri D so the metallic form of scandium will look like of this type similarly the titanium these are granules so if we have the corresponding ore from the earth crust so or for the titanium also we know that titanium dioxide tio2 is a typical or for that so titanium dioxide is there and from there we just have to go for the corresponding reduction so the mechanism is there that how how to get titanium from tio2 so in the metallic form if we produce that thing so in the corresponding granules are forming and the titanium so we that particular thing will also give us the properties what we are just now discussed that it has a lusture it has a strength and all these so the corresponding metallic properties for all these things will be there so we get that for the corresponding Vanadium also V we just once we move to vadium vadium will also give us something where the color of these things are changing so if I put something that means how nicely we look all these things that means from the nature of all these things particularly the color of all these and the metallic cluster of all these things can we can identify it immediately whether it is candium this is titanium and that is vanadium so these all different so the particular nature of this particular units that means the corresponding granules the granules the nature of these granules these are not typical powder because some other process we have to go for getting the corresponding powder similarly chromium you see the chromium also look likees a chromium powder so this a chromium powder we can have so this is a more powdery form this has less metallic luster type of corrector so it is forming a typical powder type of thing then manganes manganes you all know the most typical uh corresponding or is the pyite which is manganes dioxide which is plenty in nature India is also very much rich in having manganese dioxide or paroide so uh the mining process basically gives us the mining for manganese we take out that particular ore and the industry the the metalurgical industry will give rise to the corresponding Mangan so if we consider that in some case say we basically get that particular thing that where we can have that particular manganes typically in our hand so manganese will be for the particular manganese metallic state so these metallic State we can use sometime because most of these are as metal they can also react nicely with the acids so the oxidation process because we all know now that they can liberate hydrogen from the acid so direct reaction of all these can liberate hydrogen and the metal will go to the corresponding ions like that iron when it reacts with hydrochloric acid iron powder so this powder from the Petri what we can take so if we react with hydrochloric acid the corresponding salt what we'll be getting is the feric chloride and hydrogen Evolution can take place so the corresponding iron powder which can also be identified from the oats like hematite and magnetite Cobalt is also very much similar to that of our vanadium Cas so it has also typical lusture so is a typical globules having a shy appearance so shy appearance on the surface of this will tell you that this is a cobal thing then nickel nickel is also of different nature that means when we go for the corresponding crystallization from a molten State because all these at high temperature we are getting as in the molten State and when we go down to room temperature they basically crystallize it out in a typical form so the metallic nickel will be separated out from in this particular fashion similarly this is copper so copper is also the last pieces which we get but already we are having 4 + 4 + 8 + 9 elements we just reach there then we can have the Jin Jin we have the 3d1 arrangement because the Jin granules Jin powders and all these are very important to understand the positioning of this particular as a it is a transition element El or not but the jinc will not be a transition element because in the elemental state or in the metallic state it has the corresponding electronic configuration of 4 S2 3d10 so if we just take out those two electrons so the electrons will go from the 4S level so the 4s2 electron will go to give you a 4S Z electronic configuration living behind with 3d10 electronic configuration so that 3d10 electronic configuration will give give you a fill 3D level so jinc will not consider as a transition element so already we have discussed how we can jut down these physical properties so so as inferred by the name the transition metals are metals and thus conductors of electricity so whatever the species what we just now have seen as the corresponding metals because in some of our next classes we'll be discussing about the corresponding formation of the transition metals so if we have the corresponding metal which just now we have seen as the fe0 so it has all metallic property inherent to it but when we move from there to say f 2+ or fe3+ so this is a typical electron transfer process we all know and this is the oxidation process but whatever things will be producing in solution in water and these will be present in Aqua Solution these two are in Aqua Solution so these ions in solution so these are we can consider them as transition metal ions so whatever we have such as this present in blood if they are present in blood in this particular two forms that mean either iron 2 or iron 3 or any other biological system so those are we considered as the transition metal ions so we should always be very much particular that you have ions so these are forming with the corresponding ions not the corresponding Metals so if we just consider that this particular metals and thus they have the good conductor of electricity so the iron wires and all these things we can have we know aluminium wires like that of we have iron wires so that particular then we have the good conductor of electricity we are using electrical wires the copper wires and they are highly dense so they have high density and high melting points and boiling points also so if we consider that corresponding thing that what we get the corresponding properties is due to the progressive filling of the D Cel but the filling of these levels will give you the corresponding metallic character of these so the metals when we talk their properties are due to the corresponding zero form that means the iron zero or nickel zero and they have the typical metallic bonding so we'll not consider all these things in this particular class but we should have some little bit idea about what is called this metallic bonding so just now we have seen that in case of 4S element and the four P elements we have the ionic bond typical ionic bond and the typical covalent bond and in between we can have for 3D elements in the metallic State they can have metallic bonding and in the metallic bonding case also when we'll consider the typical bonding for the corresponding metal ions there also will find some interesting thing for their participation in the corresponding bonding when they participate as the corresponding transition metalliance but what about in the free form that means in the zero form in the metallic form they also participate for the corresponding delocalization of the D electrons and that's why they increase basically their cohesion due to the large number of these electrons because we know that the capacity of D electrons when it is filling in jinc when it is filling completely in cadmium when it is filling completely in Mary they have 10 electrons all together so so as we have discussed what is the typical indication that we are not getting as this particular one for the Mercury which is a typically different thing which is the field D level so all these not only marur but starting from Jin which is 3D uh fi so it's 4s2 3d10 then cadmium 5s2 4 d10 and then marur 5 s26 d10 so these all will have lower melting point so the melting point is less boiling point is also less because they have full d sub cells and they don't participate much in delocalization and sharing of D electrons and they don't have very good DD bonding in relation to increase the corresponding metallic bonding so the conduction band they form but the corresponding DD bonding will not participate much in forming the corresponding character and as a result the high one that means the Mercury will have a very low melting point of - 38.8 3° Cen orus 37.8 n° fah is a liquid at room temperature so is basically is failling so from that particular one that metallic property is not there but it has other properties though it is in liquid so other metallic property will be there but is not a transition metallic property we just expect from there so so the first 3D series we just now take out partly because we'll be talking about their properties because what about this D Block series so this D Block series will be there if we just simply talk in terms of the corresponding appearance of the corresponding oxidation States because just now we have seen from Scandium to jinc how they look like now if we take out the corresponding reactivity pattern of these so the one of the chemical reactivity physic physical reactivity we all know that how they form alloy what is their metallic lusture whether they conductor all these but what about their corresponding ionization so ionization is their corresponding reactivity pattern with the acid whether your acid is oxidizing or not that means the reaction with hydrochloric acid the reaction with oxidizing acids like nitric acid or sulfuric acid so that will give rise immediately whether we are able to get the corresponding salt formation that we have seen that Jin the metallic Jin or the Jin rod in our previous redox chemistry classes we have seen that Jin Rod can lead to something where the evolution of hydrogen can take place and we can give rise to the corresponding metallic salt starting from jinc oxide or the jinc itself so this particular thing that now we can just separate it out quickly from group 3 to group 11 including the group 12 because we reach ultimately the 3d10 so the atomic number the elements and the configurations so configurations we always we can have some good idea so separating out of this candium to zinc and what about this particular possibility is also there that means we once we know that the jinc then copper then nickel which is a 3d10 element then we have the 4D then 5D so jinc copper and then nickel when you reach down to nickel then downwards we have the padium and we have the Platinum similarly when we iron iron is 3d6 4s2 so if we go what we are just now seeing that if we know the configuration that means the positioning in the group The corresponding atomic number also so this we can find out is not that you have to memorize all these things but you should know that is atomic number once it is 26 by filling up the electrons from left to right from 21 to 30 where your position of the iron and its electronic configuration so if it is 3d6 4s2 so this iron which is 3d6 and 4 S2 so it is in the zero state so when it is losing two electron it is losing three electron so St Stateway will not consider the electron occupancy in this particular level so we Stateway will write that is a 3d6 ion so feros is a 3d6 ion and this particular case what we'll see that we have the most two common oxidation States so for iron here we'll just simply write as we know that also for our blood in our body that either you can have rn2 Plus or RN 3+ or something which is in between or something related to its corresponding reduced form of the fery so this f3p and this so these are most common oxidation state which is very important that how facile they are that means the formation of these by simply reacting with say dilute hydrochloric acid cold and dilute hydrochloric acid which is Aquas so the reactivity of the iron powder how we have seen that the what is the iron powder so reactivity of these iron powder will just lead to the evolution of hydrogen so hydrogen evolution can take place and the corresponding ions will remain as the chlorides are there so we having the corresponding thing as the feros chloride and if it is oxidizing because these the redox potential the redox couple between these two are less the e z value for these two are also less which is 77 volt so if oxygen is there oxygen is much more oxidizing so it is in air so if we handle everything in aqua solution so already the water present for this Aqua Solution or the preparation of this hydrochloric acid so O2 is there so this particular aqual solution so O2 is the oxidizing one so O2 is oxidizing agent so that will immediately oxidize this to F3 plus so what about this particular electronic configuration so electron configuration for fe3 we have to take out one electron from this 3d6 so it will not be 3d6 it will be 3D five so for these two that means we have 3d6 ion and 3d5 ion which are most common oxidation States for 3D level so since we are talking about 3D so if we just consider the periodic table so in the periodic table we have iron ranium and osmium so which is 3D 4D and 5D and these are having giving rise to some electronic configuration so if we consider that both of all of them are giving that means the trivalent state trivalent state for iron trivalent state for ranium and trivalent state for osmium so this is the electronic configuration which is 3d5 for iron so iron 3+ will be 3d5 so without knowing much or without bothering much about what would be for ranium so ranium will be ranium 3+ this is iron 3+ so iron 3+ will be 3d5 so ranium 3+ will also be 4 D5 similarly osmium can go for osmium 3 plus which will be 5 D5 so this is the advantage of knowing the periodicity of the elements placing them in the periodic table and how quickly we can understand when we talk about the chemistry of these because sometimes we can handle all these in solution having some test tubes we can have some test tubes test tube one test tube two and test tube three in one case we have ion in solution in another case ranium in the trivalent state in other case the osmium in the trivalent state so the generalization of all these things are very important and we know that most of these cases we are removing the electrons from the D level that means this oxidation the first one electron loss one electron loss the first one electron loss for getting fericon from feras is the removal of the electron from the D level so this is much more fasile but if we can have some arrangement and if we can have some stronger oxidizing agent so then we can find it out whether we'll be able to take out the electrons from its corresponding positioning that means whether we can go beyond that means whether we can take out more number of electrons from these that means we can take out one more electron from this level giving 3D 4 or 3d3 so those oxidation States we can get and those oxidation States will be termed as unusual oxidation States or uncommon one so uncommon oxidation States we can have that means Beyond this so two and three can be there so we can have 4 plus we can have 5 plus or we can have 6 Plus but all together what we can have all together we can have eight number of electrons two in s level and six in D level so if we remove all these electrons from s level or S cell and D level or D cell we'll be getting something which is 8 plus so whether we'll be getting that particular one is important to discuss whether it is possible for iron and whether it is possible for all other elements so what we see that getting all these oxidation states that means + 2 + 3 + 4+ 5 and plus 6 so these elements these transition elements therefore occur in variable oxidation States so they basically occur in variable oxidation States so one or the other that means as we move that means the corresponding filling off of the D level from Scandium to iron we are filling up stepwise one after another one electron two electron three electron four electron five electron and six electron similarly when we are talking in terms of the removal of electrons from that particular ular D level or D cell is the corresponding oxidation reaction so solution chemistry for all these metal ions is will be mostly dominated by the presence of the corresponding oxidation States and we should have some good knowledge about the presence of all these oxidation States in our hand so we get this as the 3D elements or D Block series in the third level similarly we get the next one which is is the second D Block series which is from y to CD or itum to cadmium and again like that of our electronic configuration or the positioning of all these things we see that in this particular case also the progressive filling of the diesel is important and we have in some cases we have the mostly from here that means D1 to D9 because this we just move for that if we move this El to the S level which will be 5s2 and which will be 3D 4 D9 we get the progressive filling of the Dell so we'll get these and since this particular one we are talking about so this particular one since the size is increasing instead of writing as D6 S2 electronic configuration we can move because these are very close by energy wise these levels are very close by the D level and the S level so we can move this particular electron to this particular cell so that is their configuration is now is 47 5 S1 so that basically tells us something that whether we can have that removal of single one electron from the S level so removal of that particular one electron will giving rise to a state where you can have ranium in 1 plus state so in a particular condition or in a situation that we'll find afterward that one particular type of compound we call as the Organo metallic compounds where we can have some interaction of this metallic state in the zero that means the powders can react with some of the species like that of our metallic state which can interact with that particular thing that means simple carbon monoxide so 3D coner of this padium is nickel we all know know that nickel can interact with carbon monoxide giving rise to tetracarbon Nickel zero so nickel will be zero in that particular case is a organometallic compound and that organometalic compound will have electronic configuration we just considered that electronic configuration in terms of nickel Zer similarly if we CH think that padium zero in different organic chemistry reactions the padium zero the metallic state of padium is important and the corresponding electronic configuration if we push all these electrons to the D level because this has a extra stability the stabilization we all know that the half field cell that's why this particular cell we are writing instead of 5 S2 4 D4 we write as 4 D5 5 S1 so one electron we move from s level to D level so it has some extra stability that means the half field cell and the full field cell so the padium in that particular case that this padium in the zero state will have a fullfill state and that fullfield D level will have a 4d1 electronic configuration and is stable similarly the other one that means the 5D block and the 5D block will get the corresponding one from that uh Lum to L sorry this lanam this lanthanum is 71 this not lutum is lanam La it LA to uh this gold so there we are also having just simply the same type of electronic configuration and same number of electron in the D level and the S level but thing is that now we can have the corresponding occupancy of these levels and is changing from one particular level to the other we are talking something related to 3D level 4D level and 5D level so the corresponding occupancy of the uh corresponding period that means the uh period which we are talking about for 3D 4D and 5D so in this particular case these are the 5D element so the kic state just now what we have discussed that osmium like iron so after iron we have ranium and then we have osmium so osmium is the coner of the iron group so in that particular case we should not forget the group number similar fashion we should know the atomic number also nicely and the osmium and the osmium is in plus two oxidation state like that of our iron will be 5d6 electronic configuration so all these things and the particular type of bonding in all these cases what we see is related to the corresponding occupancy of all these D levels and we'll just be able to consider the different thing that means the 3D 4D and 5D elements so this 3D 4 D and 5D elements so we have so if we just consider these 3D 4D and 5D elements in its Elemental state that means m is in zero state so physical properties are also changing when we talk about the bond strength so bond strength will also be changing and this particular bond strength trend is there so as we go for bigger and B bigger D level or D cell the bond strength Str will be changing and which is a different one which is a reverse one for this so this trend this trend is reverse to that normally we found for main group elements that means the S block and P block elements so what do we find for main group element is different for these transition elements so we find that once we get that that means if we consider that what about Tong St then which is in the chromium group so we have chromium mipam and Tangen so chromium mipam and Tangen we have and in this particular case chromium you know that this has six unpaired electron similarly MIP denam will also have six unpaired electron so we have five D4 and 6 S2 so all these six electrons if we consider the corresponding property as its zero state that means tungen in the metallic state so the tong in the metallic state have the six electron and these six unpaired electron they participate strongly in metallic bonding so we have large number of electrons which are not possible to get for S level or the P level elements so large number of electrons are available for this so as a result they can have also very High electro negativity so tungen will have therefore have very high electro negativity and this particular information is also important from our early school days we know that they can be utilized so they have a very high melting point and high boiling point so tungen the metallic tungsten will have very high melting and high boiling point and as a result they can be utilized for making the bulb filament so the bulb filaments for incandescent lamps we use tongen as the corresponding material for the making of these ball filaments so we can have these that means we just corresponding unpaired electron so we basically change the corresponding melting point so we just can see also what about the corresponding melting point Trends also so as we move from Scandium to Titanium to ultimately to zinc so we find that the typical melting point in deg centigrade will also be changing and which are above 100 so mostly it is above th000 so not sorry Above th000 So above 1,000° centigrade and in some cases they can go up to 3000° cenr so one value is 1539 de Centigrade for Scandium so it is increasing for titanium it is increasing for vanadium as well as chromium but in case of jinc it is less since those number of electrons which are there but is in the field cell it is not available for that kind of metallic bonding so minimum will be find ing over here where the levels are filled so the melting point Minima will be finding over here and melting point Maxima will be here for the transition M line so thus we see that number of electrons in the elemental State we not forget that all are in the elemental state that mean the Scandium as the metallic Scandium tianium as the metallic Scandium they have the high melting point High in point and some of these uses related to the metallic state so the next day we'll be just considering how we get for the corresponding electron transfer reaction for the oxidation that means the availability of the different oxidation States okay thank you very much for