 Yeah, can you hear me in next write down characteristics of once again characteristics of of the compounds of group two elements Compounds of group two elements the first compound that we have is Oxide formation that is oxides Okay, see we have different different types of oxides. They forms normal oxides. That is mono oxide ammotype It also forms peroxides of MO2 type right, so write down all elements Forms oxides of ammotype elements forms oxides of Ammo type This is mono oxide basically right on these elements also forms peroxides of peroxides of MO2 type So mono oxide and peroxides of MO2 type it forms, okay does not form peroxide BE does not form Peroxide all these oxides peroxide forms because of the Stabilizing effect of the cation Okay, the positive field that we have on the the positive ion that we have basically right if you talk about the positive charge on the element which is present on the top like B plus 2 mg plus 2 and all so because of high charge density over there these oxides are quite stable This v plus 2 and mg plus 2 Stabilize the oxide ion o minus 2 and hence the oxides are stable over there correct these oxides are also strong like I said stable, but it is strong enough It is not strong enough to prevent the formation of OO bond which is there in peroxide To prevent the formation of peroxide, but super oxide it does not form means whether the molecule will form Oxide or peroxide or super oxide it depends upon the stability of the cation Right, so cation is a strong enough to stabilize the mono oxide and peroxide But it cannot stabilize super oxide and hence super oxide does not form Okay, right down as we go down the group for peroxide you write down as we go down the group as we go down the group That's stability down the group the stability of peroxide increases Oxide increases Since be be does not form peroxide, so I'm not writing it down here mg o2 is least stable Then we have ca o2 SR o2 and ba o2 the stability order we have this The metal is directly allowed to react with oxygen Yeah, we'll try to finish all important things whatever few things is left I will ask you to you know go through on your own Okay, depends like what all things we can cover. I think we can cover most of the things We have one hour so we can cover those quickly write down and Then I'm planning to start thermodynamics next class. Okay thermodynamics or equilibrium. We'll see that Okay, you see how do we prepare the you know the oxides? oxides are prepared by the direct reaction of metal and oxygen Okay, converts into M o where this M is M is Beryllium this is important here M is we can have beryllium We can have magnesium We can have calcium Stronchium and Beryllium Right, sorry, Beryllium is not possible. I guess how Beryllium is not possible Beryllium we cannot prepare Beryllium oxide. We cannot prepare by this method Tillitronium Okay When Beryllium reacts with oxygen directly it converts into peroxide. You see this Beryllium plus O2 it converts into B a2 Down the group you go tendency to form peroxides increases. So Beryllium Beryllium gives you peroxide not monoxide We cannot form BAO by this method you keep that in mind We can also obtain monoxide By the decomposition of carbonate MCO3 heat this MO plus CO2 Okay, MSO4 sulphate Sulphate you heat this It is MO plus SO3 few characteristics you write down all monoxides Except BEO, you know the reason behind this our Inic BEO is covalent in nature presence rule these oxides are highly stable these oxides are highly stable BEO is amphoteric This is amphoteric Reaction which shows its amphoteric behavior is see this BEO reacts with 2 HCl converts into BECl2 plus H2O reaction with acid with base you see 2 NaOH It forms Na2 BEO2, which is sodium beryllate other oxides are basic in nature reacts with Water you see MO plus H2O and we know it forms Hydroxide the reaction is exothermic basic character of these hydroxide of these hydroxides Increases down the group Increases down the group size increases so bond length increases Bond strength decreases and tendency to release more OH minus ion in the solution. That is a basic character next slide down sulphur reaction means Which reaction? That's how this one sulphate. Okay So if you see this Next point you write down the oxides have oxides have High lattice energy lattice energy and hence and hence Stable lattice energy and hence they are stable as we go down the group Size increases as we go down the group size increases hence Lattice energy decreases Correct. So these are few properties. We have that you must remember for oxides and hydroxides hydroxides will see For oxides basically Okay, next the second type of compound it forms We call it as hydroxides hydroxides In general, we say when mono oxides reacts with water it converts into M OH whole twice and heat releases correct heat releases, but this is not for the Be OH 2 or Mg OH 2 beryllium and magnesium is not possible here means this M is Only equals to calcium strontium and beryllium So how do we obtain be OH whole twice and Mg OH whole twice beryllium hydroxide and magnesium hydroxide beryllium and magnesium hydroxides are prepared by dissolving Their sulphate in water so it forms be OH whole twice We get any two SO4 Similarly Mg SO4 plus H2O Mg OH whole twice once again This reaction. Okay, so we have any OH also here Solution of any OH we use Okay, any OH with water this solution we have and hence we also get here any two SO4 So be beryllium sulphate and magnesium sulphate is dissolved in The aqua solution of any OH which gives you this reaction now the properties you see like the first one be OH whole twice is Amphoteric is amphoteric in nature reacts with both Acid and base as we go down the group down the group this point already I've given you Down the group the basic strength the basic strength increases since the size increases more tendency to lose OH minus ion Okay, second point you see thermal stability of hydrides thermal stability thermal stability One second. We're talking about thermal stability means reactivity towards stability towards heats, right? Okay, so hydroxides we have correct so thermal stability right now thermal stability as we go down the group wait Thermal stability increases as we go down the group when you have suppose Mg OH whole twice and You heat this it converts into oxides and and Let's do okay. Next. We'll see the solubility Write down as We go down the group the solubility Increases as we go down the group the solubility Increases see solubility right on solubility depends upon Solubility depends upon the lattice enthalpy lattice enthalpy and hydration enthalpy the lattice enthalpy and hydration enthalpy Both lattice enthalpy and hydration enthalpy right on this point both Lattice and hydration enthalpy hydration enthalpy decreases down the group Decreases down the group if you talk about the relative decrease that decrease in lattice enthalpy is More rapid than that of hydration enthalpy next slide right down the decrease or Allowed on this way the lattice enthalpy the lattice enthalpy decreases decreases more rapidly more rapidly Then hydration enthalpy and when lattice energy decreases. So obviously solubility increases the decrease in Lattice enthalpy is more it decreases a lot in comparison to hydration enthalpy and hence the solubility increases then Next you see highlights write down elements of group 2 forms halides of Mx2 type Mx2 type highlights of beryllium BE x2 Are covalent? Again the same reason Only highlights of beryllium is covalent All other elements highlights are ionic in nature. If you talk about the ionic character of these highlights ionic character BE x2 is The least ionic impact it is covalent and we know as we go down the group the ionic character Increases covalent character decreases so any orders this One more point to write down the compound which is more covalent Can be easily hydrolyzed? Okay, so we can write down like this hydrolysis is Easier of covalent compound for example if you need to write down the order of hydrolysis of Vecl2 MgCl2 CaCl2 Bacl2 That's a SRI forgot. So we have SrCl2 and Bacl2 Hydrolysis is this Because it is the most covalent covalent compound can be easily hydrolyzed write down BE f2 BE f2 has random structure other highlights of beryllium But other highlights of beryllium other highlights of beryllium are crystalline crystalline is they have a different pattern fixed structure Are crystalline? Like you see Bacl2 and write down this is important Becl2 has different structures in different state like you see Becl2 in vapor state in Vapor state in vapor state Write down it exists as monomer Vapor state exists as monomer Zero dipole moment with zero dipole moment, but this is possible When temperature is greater than 1200 Kelvin, so when temperature is greater than 1200 Kelvin So at this temperature, its structure is pretty simple BE and Ca This is the structure with single bond okay, but when the temperature is less than 200 Kelvin 1200 Kelvin Then it exists in dimer form Right exist in dimer form if you look at the structure the structure is this We have Cl here beryllium Cl and Cl and this chlorine is in the same plane So it exists as dimer This one is monomer because we have only one molecule. This is in vapor state Vapor state on different different temperature more than 1200 Kelvin monomer Less than 200 Kelvin dimer Okay, next if you look at this structure of Becl2 in solid state in solid state in solid state it exists in polymeric form or It has polymeric structure polymeric structure. For example, you see beryllium chlorine beryllium chlorine and chlorine and Again, this is, you know, it is coming Out of the plane beryllium coming out of the plane out of the plane like this and Then again in the same plane and then this side we have again out of the plane This side also we have Okay, so this is the three different structures exist in two different states at different different temperatures So this is a structure you must remember it is important then copy Okay, next write down carbonates and bicarbonates carbonates and bicarbonates Okay, write down See carbonates we can prepare in two different way. I'll write down the reaction here directly The reaction is first of all you can take hydroxide moh whole twice aqueous And you dissolve this in CO2 this converts into M2 CO3 aqueous and H2O forms We can also use sodium or magnesium carbonate like you take mgCl2 suppose magnesium or carbonate you need to form So you take mgCl2 aqueous aqueous and dissolve this into sodium carbonate that is any 2 CO3 aqueous Then from this what happens mg2 mg co3 forms mg co3 forms And We get NaCl here This two won't be there This two will not be there because mco3 type carbonates will get These two methods we can prepare carbonates Write on thermal stability As we go down the group thermal stability increases thermal stability increases Okay, the reason for this is There's a fact called large cation large cation can stabilize Can stabilize large ni So as you go down the group the size of cation increases metal ion increases and hence the stability of carbonate ion is more Okay, carbonate ion is a big guy Right sulphate ion carbonate and these are the big ions here So for all these ions if you think of the bond length Then you'll get the reverse order Because down the group if you go bond length increases thermal stability should decrease That is not happening here, right here. It is happening because of the stability of anion So stability of anion is more because of the large size of cation and hence down the group The stability of carbonate increases thermal stability Okay important order this one So if I write down the order here Be co3 is least stable Then we have mg co3 ca co3 sr co3 And ba co3 Solubility in water of this carbonates you see as you know thermal stability increases down the group And hence the solubility decreases So as you go down the group thermal stability increases solubility decreases down the group as thermal stability increases thermal stability increases by carbonates you see It is prepared by first of all the reaction of hydroxide with carbon dioxide Which gives carbonate m co3 H2O comes out and then when this carbonate is dissolved in aqua solution of co2 saturated Then this converts into m h co3 bicarbonate Whole twice Get on all body bicarbonates Are stable in solution all bicarbonates Are stable in solution next You see nitrates There are three different way by which we can prepare nitrates One is you take monoxide And dissolve into hno3 So it converts into n o3 twice plus water There is nitrates If you take hydroxide Again in hno3 It forms m n o3 whole twice Achai made a mistake. This is only h2b hydrogen gas evolves here plus will get water to h2o with hydroxide If you take carbonate m co3 Again, you dissolve this into hno3 will get m n o3 Plus co2 Plus h2o This is the three way we have by which we can prepare nitrates Yes, you see as size increases hydration enthalpy hydration enthalpy Decreases and hydration enthalpy decreases means hydration decreases hydration You know size increases down the group so we can say hydration decreases as you go down the group nitrate o3 twice When you heat this It dissociates into oxides monoxide n o2 n o2 comes out So nitrogen dioxide evolves. This information is important nitrogen dioxide evolves last We have three more to discuss in this sulphates nitrites And carbides these three Not a big one small small things are there will finish by time So next is we have sulphates Four different way by which we can prepare sulphate Metal you dissolve into h2o4 converts into mso4 plus h2o oxide monoxide you take Again, you dissolve into h2o4 So it forms obviously mso4 will get sulphate With oxide we have water evolves If you take hydroxide mOH whole twice Dissolve into acid again h2so4 converts into mso4 Plus two h2o carbonate plus h2so4 converts into mso4 Plus CO2 Plus h2o for this also we have the same thing thermal stability increases down the group So if you talk about BE SO4 MG SO4 CAS SO4 SR SO4 thermal stability decreases down the group same reason we have thermal stability decreases down the group correct thermal stability increases so obviously solubility in water decreases exactly the same logic solubility decreases because more stable less solubility solubility decreases then copy Okay, next you see nitrides see all metals when heated with nitrogen forms nitrides of m3 and 2 type all nitrides Property you see all nitrides are colorless crystalline compound except Except which one could you tell me the first one right that is what you know the abnormal behavior we have except BE3 and 2 Okay, these nitrides when dissolved in water m3 and 2 dissolved in water It evolves ammonia and along with ammonia will get hydroxide will get NH3 evolves ammonia gas reaction with carbon monoxide is a bit different for the different elements you see here m3 and 2 When reacts with carbon monoxide it forms monoxide and n2 releases nitrogen gas comes out into this where this m here is We can have magnesium We can have calcium We can have strontium Okay Badium reacts in a different manner BA3 and 2 reacts with co It forms barium oxide and BA CN2 This is the reaction we have copied Okay The last one is carbide Two different types of carbide these elements forms In fact 3 write on alkaline earth metal earth metals forms three different types of carbide it can form m2c type It can form mc2 type and it can form m2c3 type carbide m2c type carbides Forms only by beryllium Only by BE so only we have BE 2c exist in this case Okay, this is formed by all the elements we can have different conditions for preparation But all elements can form this kind of hydrides This is also formed by all elements, but mainly magnesium reaction we'll see here Mainly magnesium So if you see the first type here, that is m2c type You know m is beryllium over here So first is so beryllium directly reacts with carbon Around 1900 to 2000 degrees Celsius And it converts into BE2c Okay, we can also take The oxide of beryllium Suppose 2 BEO with 2c Converts into BE2c Plus 2co this reaction is also very high temperature Uh around 2000 degrees Celsius. We have this reaction. Okay. So once they have asked this question in JE Which gas evolve when the carbide? I'm not sure with with you know What metal was there? But this was the you know, the idea of the question was this BE2c, suppose we have this carbide when this carbide dissolved in water Then which gas evolve here? right So obviously you should know the reaction The reaction is We have BEOH whole twice And CH4 4 so methane gas is the answer How do you memorize this? We have BE2c So BE2c actually dissociates as 2 BE2 plus since it is the Metal of second group. So it will always have plus 2 charge on it And BE2 we have it means 2 BE plus 2 will have 2 BE plus 2 will have total four positive charge It means carbon should also have four negative charge C4 minus And since carbon has four negative charge This is only possible When it forms CH4 Right since four negative charge it requires four hydrogen And hence CH4 will get so this is how we can memorize this reaction second type you see mc2 type carbide Like I said it is prepared by all alkali metals beryllium you see beryllium is allowed to react with acetylene forms BE2 And hydrogen gas releases If you take calcium Calcium directly reacts with carbon At high temperature 1100 degrees Celsius Forms CaC2 Condition is different again It can also be obtained by oxide of calcium you take You take carbon and you heat it around 2000 degrees Celsius CaC2 Plus CO So we have three CO here now on this the question that they ask here this type you see similar kind of questions That suppose if you dissolve calcium carbide CaC2 in H2O Then which gas evolves over here You see here Ca again it converts into Ca2 plus C2 2 minus will have you 2 carbon with 2 negative charge it means the possible reaction is Product is here. We obviously get CaOH whole twice calcium will plus 2 And this would be C2 H2 that is acetylene evolves in this reaction The last type you see M2 C3 type carbides Mainly formed by magnesium The reaction is 3 mg Plus acetylene Converts into Mg2 C3 Plus H2 2 mg 3 Sorry 3 C2 so it would be 6 So we have 2 here and this is 4 6 hydrogen so 3 H2 this is the balanced reaction here mg2 C3 Again you see when it dissociates It gives what? 2 mg 2 plus And this side we get C3 4 minus So when this dissolve in water mg2 C3 Dissolve in H2O It gives hydroxide We get C H3 C triple bond C H Propine So all these carbides hydrolysis reaction is important. You must do this Done copied Yeah finished Okay, so we are done with this. Okay almost done only a few things is left Like I'm going to you know tell you what all things you have to study In ncrt or any other book you have but ncrt you have to Read it read completely from beginning to end properly. Okay So only a few compounds, you know small small reactions out there, which is left What you need to do At home is You finished Magnesium hydroxide not much important Magnesium sulphate mgso4.7 H2O Okay, some properties and you know reactions. We also call it as ipsum salt quick lime you finish CaO Calcium hydroxide You'll get only four five reactions not much. Okay, and the last one in this you must do a little bit of about Cement and plaster of Paris plaster of Paris This five six points is very small small topic it is There is no, you know logic at least some carbonate stability sulphate stability and all there are some logic orders We have stability and all here. We have just reaction and all that you can memorize Okay, so these things you finish ncrt or if you have any other book Yes, if everything is given in ncrt go through it. Otherwise, I think few Things will not be there Probably if it is not there then you can refer any of the book But ncrt the entire chapter you have to do from beginning to end Okay, so this is it for this chapter next class. We'll start with either equilibrium Or thermo. I'll see that. Okay. Yeah, thank you guys. Take care. Bye