D AND F BLOCK CHEMISTRY PDF
The presence of partly filled d or f orbitals in their atoms sets the study of the transition elements and. The d- and f-. Block Element. d- Block elements are collectively known as Transition Elements because 1)d &ns orbital as a result both (n-1)d &ns electrons take part in bond formation. “The elements in which the last differentiating electron enters into the d-orbitals of the penultimate shell i.e.. (n–1) d where n is the last shell are called d-bloc.
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Free PDF download of Class 12 Chemistry revision notes & short key-notes for Chapter 8 - The d and f Block Elements to score high marks in exams, prepared. d-Block elements occupy the middle portion of the periodic table i.e. between s- . that 4s orbital (l = 0 and n = 4) is of lower energy than 3d orbitals (l = 2 and n. 10_ d - And f - Block myavr.info - Read online for free. has incompletely filled d-orbitals in its ground state or any one of its oxidation states. There are four.
Mercury is liquid at room temperature m. Osmium has slightly lower density Thus, iridium has the highest density among transition metals. Some are almost inert and known as noble metals, e. Colour of a complex depends on the metal, its oxidation state and its ligands, e. Charge transfer also give intense colour e. Charge transfer is possible only when the energy levels on the two different atoms involved are fairly close. Paramagnetic character increases with increase in the number of unpaired electrons and highest for Mn II [among 3d-series].
Alloys so formed have high m. Amalgam is an alloy formed by mercury with other metals, Iron and platinum do not form any alloy with mercury. List of Alloys xv Interstitial compounds The vacant space present in a crystal lattice is known as interstitial site or void.
The non-metal atoms e. Such compounds are hard and rigid, e. It is due to the variability of Oxidation state in the transition metal. These elements form such compound by trapping H, B, C and N etc. In inverse spinel, the trivalent ion occupy the tetrahedral holes and divalent ion occupy the octahedral holes.
Some important reagents having transition metals 1. Lucas reagent HCl cone.
The D and F-Block Elements Class 12 Notes Chemistry The d -Block elements: The elements lying in the middle of periodic table belonging to groups 3 to 12 are known as d — block elements. Their general electronic configuration is where n — 1 stands for penultimate last but one shell. Transition element: A transition element is defined as the one which has incompletely filled d orbitals in its ground state or in any one of its oxidation states.
Zinc, cadmium, mercury are not regarded as transition metals due to completely filled d — orbital. The f-Block elements: The elements constituting the f -block are those in which the 4 f and 5 f orbitals are progressively filled in the latter two long periods. Lanthanoids: The 14 elements immediately following lanthanum, i.
They belong to first inner transition series. Lanthanum 57 has similar properties. Therefore, it is studied along with lanthanoids. Actinoids: The 14 elements immediately following actinium 89 , with atomic numbers 90 Thorium to Lawrencium are called actinoids.
The d- and f- Block Elements class 12 Notes Chemistry
They belong to second inner transition series. Actinium 89 has similar properties. Therefore, it is studied along with actinoids. Four transition series: 3d — transition series.
The transition elements with atomic number 21 Sc to 30 Zn and having incomplete 3d orbitals is called the first transition series. It consists of elements with atomic number 39 Y to 48 Cd and having incomplete 4d orbitals.
Oxides in the lower oxidation states are generally basic in nature and those in the higher oxidation states are amphoteric or acidic in nature. It is prepared from the chromite ore.
Different reactions involves in the preparation of potassium dichromate from chromite ore are: Potassium dichromate is a powerful oxidizing agent. Potassium dichromate is used as primary statndard in volumetric analysis. This produces the dark green potassium magnate, K2MnO4 which disproportionates in a neutral or acidic solution to give purple permanganate.
Potassium permanganate is a dark purple crystalline solid. On heating it decomposes at K and O2 is evolved.
Class 12 Chemistry Revision Notes for Chapter 8 - The d and f Block Elements
Few important oxidizing reactions of KMnO4 are given below: In acidic medium potassium permanganate oxidizes: They are characterized by filling of the 'f' orbitals.
Some of the trivalent ions of lanthanoids are coloured. This is due to the absorption in visible region of the spectrum, resulting in f-f transitions they have partily filled orbitals. All lanthanoids are highly electropositive metals and have in almost similar chemical reactivity. In lanthanoid, with increasing atomic number, the atomic and ionic radii decreases from one element to the other, but the decrease is very small.
It is because for every additional proton in the nucleus, the corresponding electron goes into a 4f-subshell, which is too diffused to screen the nucleus as effectively as the more localized inner shell.
Hence, the attraction of the nucleus for the outermost electrons increases steadily with the atomic number. Write down the electronic configuration of: In its first half i. To what extent do the electronic configurations decide the stability of oxidation states in the first series of the transition elements?
Illustrate your answer with example. To a large extent, the electronic configurations decide the stability of oxidation state in the first series of transition elements.
Elements with larger number of oxidation states are found in or near the middle of the series e. The elements with lesser number of oxidation states are present at the extreme ends stems and they have a few electrons to lose or share e. Sc 3d14s2 , Ti 3d2s2 or too many electrons hence fewer orbitals are available e.
Cu 3ds1 Zn 3ds2 etc. What may be the stable oxidation state of the transition element with the following d electron configurations in the ground state of their atoms: Name the oxometal anions of the first series of the transition metals in which the metal exhibits the oxidation state equal to its group number. MnO4, permanganate. On moving from lanthanum La to Lutetium Lu , a gradual decrease in size of lanthanoids is observed with increase in atomic number. This is known as lanthanoid contraction.
Consequences i The properties of 4d and 5d elements closely resemble because of lanthanoid contraction. What are the characteristics of the transition elements and why are they called transition elements? Which of the d block elements may not be regarded as the transition elements? Characteristic of Transition Elements i They belong to d block of the periodic table.
They are called transition elements because their properties lie in between those of s block elements metals and p block elements non metals. They are more electropositive than s block elements but less electropositive than p block elements. In what way is the electronic configuration of the transition elements different from that of the non transition elements?
In case of transition elements the incoming electron enters n 1 d orbitals whereas is case of non transition elements i. In case of transition elements the last two shells are incomplete whereas in case of non transition elements only the last shell is incomplete and is being progressively filled up.
Explain giving reason: The unpaired electron present in them undergo d d transition by absorbing light from the u. Why are such compounds well known for transition metals? Crystal lattices of transition metals have interstitial voids in between the adjacent atoms, consequently, the small sized atoms like H, B, C, N etc.
The chemical properties of interstitial compounds are quite similar to those of parent metal, however in physical properties such as hardness, rigidity and electrical conductance these compounds differ from parent metal.
There is a decrease in malleability and ductility but an increase in tenacity. It is due to formation of interstitials of iron with carbon in case of steel and cast iron.
Illustrate with examples. In transition metals the oxidation states differ by 1 e. The variable oxidation states of transition metals are due to availability of both n 1 d and ns orbitals which have nearly same energy where as the variable oxidation state in non transition metals are due to the availability of ns2np16 electrons for bond formation.
What is the effect of increasing ph on a solution of potassium dichromate? It is prepared as under: Sodium chromate is extracted with water and acidified.
Effect of pH The chromate ion, CrO42 and dichromate ion Cr2O72 exist in equilibrium and interconvertible by alternating pH of the solution.
Potassium dichromate acts as a strong oxidizing agent in acidic medium.
How does the acidified permanganate solution reaction with a iron II ions b SO2 c oxalic acid? Write the ionic equations for the reactions. KMnO4 is prepared from Pyrolusite as follows. Pyrolusite is fused with potassium hydroxide and the molten liquid is stirred in presence of air when the following reactions occurs and K2MnO4 potassium manganate is formed: Give reason for each.
Their colour is due to presence of unpaired electrons in them.
The d-and f-Block Elements Class 12 Notes - Chapter 8
The unpaired electrons in them can undergo d d transitions by absorbing light from visible region and the complementary colour in radiated. How is the pig iron converted into steel? Describe any one method of steel making in detail. Chief ore of iron is haematite Any one of the following processes can be used to convert pig iron into steel.
The furnace is adapted for different types of pig iron feed by using acidic or basic lining. The impurities get oxidized by iron oxide and form slag with the lining. Towards the end after 10 hours , an alloy of Mn, Fe and C Spiegleisen is added along with alloying metal. Describe the principle of extraction of these metals from the respective ore.
It is concentrated by froth floatation process. The concentrated ore is roasted in a current of air in a reverberatory furnace, below the fusion point, to remove arsenic and sulphur as their volatile oxides. The matte consists of Cu2S and FeS. The mate is charged into silicalined converted through which hot compressed air is passed. The remaining sulphide is converted into FeO which reacts with silica to form slag.
Copper I sulphide is reduced to copper by Cu2O. Impure copper is made the anode, pure copper is taken as cathode and acidified CuSO4 solution is taken as electrolyte. When electrolyzed pure copper gets deposited at cathode and impure copper from anode goes in solution.Copper Reason.
It is used in cleaning glassware. Adnan Depar. Previous Year Question Paper. It is due to the variability of Oxidation state in the transition metal.
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