Answer: (ii) Zinc is not regarded as a transition element (i) Cu (I) ion is not stable in an aqueous solution. 8788563422. (ii) The E° value for the Mn3+/Mn2+ couple is much more positive than that for Cr3+/Cr2+ couple or Fe3+/Fe2+ couple. They have the ability to form complexes with ligands such as chlorides, sulfates, etc. Assign reasons for the following: Answer: Give reason. because they are bigger, the outermost shell is further away from the nucleus. Answer: The elements, in the first half of the series frequently exhibit higher oxidation states. to Q.55 (i). Explain: Higher oxidation states are usually exhibited by the members in the middle of a series of transition elements. Hence, they can easily participate in bonding and therefore, exhibits more number of oxidation states. For example: (iii) Transition metals in general act as good catalysts. (iii) The highest oxidation state of a transition metal is exhibited in its oxide or fluoride. to Q.38 (ii). Oxidation State of Actinides. (i) Mn because it has five unpaired electrons and 2 electrons in s-orbital which can take part in bond formation, therefore, it shows maximum number of oxidation states. (ii) Lanthanoids show limited number of oxidation state, viz. Explain giving reasons: (At. Books. (a) (i) Transition elements form interstitial compounds. (ii) It is due to presence of unpaired electrons which undergo d-d transition by absorbing light from visible region and radiate complementary colour. Give reasons for the following observations: (i) Transition elements and their compounds are known to act as catalysts. There is a greater range of oxidation states, which is in part attributed to the fact that the 5f, 6d and 7s levels are of comparable energies. (i) MnO is basic whereas Mn207 is acidic in nature. (a) The Mn2+ compounds are more stable than Fe2+ towards oxidation to their +3 state. (a) (i) Oxygen can form double bond, therefore, it can form Mn207, whereas ‘F’ cannot form double bonds, so, it can form MnF4. (a) Complete the following chemical equations for reactions: (i) In the series Sc (Z = 21) to Zn (Z = 30), the enthalpy of atomisation of Zn is the lowest. (ii) Mn has electronic configuration (Ar) 4s2 3d5 and all the electrons in ‘s’ as well as ‘d’ orbitals can take part in bond formation, therefore, it shows + 7 highest oxidation state. (iv) The value for copper is positive (+ 0.34 V). (iii) Transition metals and their compounds act as catalyst. (ii) Oxalic acid (C2H204) (iv) It is because of high ionisation enthalpy of Cu which is not compensated by hydration energy. (i) It is because they show variable oxidation states and have vacant rf-orbitals Answer: Request a Tutor. to Q.62 (a) (i). (i) The enthalpies of atomization of transition elements are quite high. Lanthanide oxidation states All of the lanthanide elements are commonly known to have the +3 oxidation state and it was thought that only samarium, europium, and ytterbium had the +2 oxidation readily accessible in solution. to Q.35 (i). Question 41: to Q.51 (i). For example: Answer: Obviously, reaction (4.4.17) right is the reverse of reaction (4.4.11).From laboratory investigations and studies of plant data, it has been noticed that reaction (4.4.17) does not reach the equilibrium. (ii) E°CU2+/CU *ias +ve value due to high ionisation enthalpies and sublimation energies and lower hydration energy. (i) It is because of strong metallic bonds due to large number of unpaired electrons in d-orbitals. For example: +4, +5 and + 6, +7 due to small energy difference between 5f, 6d and 7s subshells. Answer: Answer: 4f and 5d levels being close in energies. Answer: (ii) Refer Ans. Explain the following observations: to Q.30 (iii). to Q.23 (a). V = 23, Cr = 24, Mn = 25, Fe = 26) (ii) Mn04– + SO2– + H+ ———> (b) Account for the following: Actinides show variable oxidation states because of the smaller energy gap between 5f, 6 d and 7s orbitals. (ii) There is a close similarity in physical and chemical properties of the 4d and 5d series of the transition elements, much more than expected on the basis of usual family relationship. 21) salts are white. Another way to prevent getting this page in the future is to use Privacy Pass. Question 37: (b) (i) Refer Ans. MnO4– + 8H+ + 5e- ———-> (ii) It is due to their small size, high charge and availability of vacant d-orbitals, Question 13: to Q.23 (b). However, there is a compensatory effect in that elements in higher oxidation states generally get more out of bonding. Sc shows maximum + 3 and Mn shows + 7, V( + 5), Gr( + 6), Fe( + 3), Ni( + 2), Co( + 3), Cu( + 2) and Zn( + 2) oxidation state. (a) Copper exhibits +1 oxidation state frequently due to stable electronic configuration. (ii) The metallic radii of the third (5d) series of transition elements are virtually the same as those of the corresponding members of the second series. I know that this may be an overgeneralization, since depending on the type (i.e metals, non metals, etc) it will be different. The +4 oxidation state is the most stable in … (b) Why do actinoids show wide range f oxidation states? (i) Refer Ans. Explain the following observations: Mn207. As the oxidation state of the metal increases, so also does the amount of splitting of the d orbitals. (a) Complete the following chemical equations: The highest oxidation state is equal to the total number of electrons in ‘s’ as well as of-orbitals. 3MnO4– + 4H+ ———> (iii) It is because lanthanoid lose 2 electrons from 6s orbitals and one from 5d – or 4/ orbitals and are stable in +3 oxidation state. Atomic number (Z) = 27. to Q.16 (a) (ii). (a) Account for the following: of Ce = 58] (ii) It is due to lanthanoid contraction, the ionic size of 4d and 5d transition series in similar. It was reported that in alkaline solution americium can be oxidized to the heptavalent state, but these data proved erroneous. Solution Show Solution Actinides exhibit larger oxidation states because of very small energy gap between 5f, 6d and 7s sub-shells . (iii) Lanthanum and Lutetium do not show colouration in solutions. 58)? Example: TPSS 435 (iii) It is due to involvement of unpaired ((-electrons to form strong metallic bond. The (n+l) values of the tree orbitals are as under: 5 f = 5 + 3 = 8. (ii) Transition metals form alloys. Manganese. (i)K2Mn04 from Mn02? (b) Why do actinoids show a wide range of oxidation states? (iii) Refer Ans. (i) With the same d-orbital configuration (d4), Cr2+ ion is a reducing agent while Mn3+ ion is an oxidising agent. Answer: (ii) It is because transition metals in lowest oxidation state are more metallic and in higher oxidation state are least metallic, therefore, oxides in lower oxidation state are basic, whereas in higher oxidation state are amphoteric/acidic. (iii) Oxidation state : The most common oxidation state of lanthanoids is +3 while actinoids show more variable oxidation states than lanthanoids ranging from +3 to +7. to Q.9 (ii). to Q.29 (i). (a) Complete the following chemical reaction equations: (iii) The highest oxidation state of a metal is exhibited in its oxide or fluoride. But the most common oxidation state of actinoids is +3. No. (iii) Among the 3d series of transition elements, the largest number of oxidation states are exhibited by manganese. Iron. Question 23: Zn+2 salts are white while Cu+2 salts are coloured. (iii) 2MnO4+ 4KOH + 02 ———> 2K2Mn04+ 2H20, Question 11: (iii) 2MnO4– + 16 H+ + 5C204– ———-> 2Mn+2 + 8H20 + 10CO2, Question 10: (ii) Oxidation state: Transition metals show variable oxidation states due to tendency of ‘d’ as well as ‘s’ electrons to take part in bond formation. Account for the following: Question 64: It has surface oxidation when exposed to air. (iv) The silver atom has completely filled d-orbitals (4d 10 ) in its ground state, yet it is regarded as a transition element. (iii) It is because they show variable oxidation states and form unstable intermediates which readily change into products. Answer: I’ve noticed that some answers refer to the word valence as if you mean number of bonds and other answers refer to the word as if it means the charge. Taking another example from chromium chemistry involving only a change of oxidation state (from +2 to +3): (ii) Name the element which shows only +3 oxidation state. (ii) 2Na2Cr04 + H2S04(conc.) (ii) Actinoids exhibit greater range of oxidation states than lanthanoids. Question 17: Question 44: (i) Refer Ans. Question 40: (ii) There occurs much more frequent metal-metal bonding in compounds of heavy transition elements (3rd series). (i) They show variable oxidation state. Zn+2 salts are white because it does not have unpaired electron, whereas Cu+2 salts are coloured because it has unpaired electron and undergoes d-d transition by absorbing light from visible region and radiate blue colour. Describe the preparation of KMn04 from pyrolusite ore (MnO4). Question 8: (ii) The actinoids exhibit a large number of oxidation states than the corresponding members in the lanthanoid series. (a) Refer Ans. (a) The decrease in atomic and ionic size with increase in atomic number is called lanthanoid contraction. (ii) It is due to 5f electrons which are more effectively shielded than 4f electrons therefore, outer electrons are less firmly held and available for bonding in actinoids and they show a wide range of oxidation states. (b) Give an explanation for each of the following observations: because they are bigger, the outermost shell is further away from the nucleus. To reach a higher oxidation state, one obviously has to pay for it in the form of ionisation energy/energies. How would you account for the following? Originally, the term was used when oxygen caused electron loss in a reaction. (iv) Mn3+ (3d4) has 4.unpaired electrons, therefore, it is more paramagnetic than Cr3+) which has three unpaired electrons. that means the ionization energy is lower for the corresponding oxidation state compared to lanthanides. Cloudflare Ray ID: 600a3b03883b16ee Identify A, B, C and write the reactions involved. Therefore all these three sub shells can participate. Sc = 21, V = 23, Ti = 22, Mn = 25) Answer: (iv) Name a member of the lanthanoid series which is well known to exhibit + 2 oxidation state. (i) It is due to smaller size of transition metals and strong metallic bonds due to presence of large number of unpaired electrons. Determine the oxidation states of the elements in the compounds listed. Therefore, its salts are white. to Q.29 (iii). Question 59: The decrease in size with the increase in atomic number among lanthanoids is called lanthanoid contraction. But the most stable oxidation state of Lanthanides is +3. no. (i) KMn04-(heat) ——-> (ii) Cr2072- + 14H+ + 6Fe2+ ———–> Question 45: (ii) Scandium (At. - or - email: password: Log in Forgot password? Copper atom has completely filled d-orbitals in its ground state but it is a transition element. Question 6: forming unstable intermediates which readily change into products. Actinides form basic oxides and hydroxides. (ii) Transition metals form coloured compounds (ii) CrO4– + H+ ——-> Answer: Explain the following observations: (ii) It is due to large number of unpaired electrons in d-orbitals in middle of the series. (ii) Actinoids exhibit a much larger number of oxidation states than the lanthanoids. Misch metal is an important alloy which contains some of the lanthanoid metals. It is attained by removing outermost 2 electrons of 6s electrons and 1 electron from 4f electrons. (ii) Tendency to form oxometal ions increases from Sc to Cr and then decreases due to increase in unpaired electrons and ability to form multiple bonds with oxygen. (a) (i) Refer Ans. (c) Which of the 3d-block elements may not be regarded as the transition elements and why? (i) Refer Ans. Answer: (ii) There is a general increase in density from titanium (Z = 22) to copper (Z = 29). Answer: (b) 3MnO4– + 4H+ ——–> MnO2 + 2MnO4– + 2H2O. (ii) They form coloured ions. The most common oxides are of the form M 2 O 3, where M would be one of the elements in the Actinide series. (i) Transition metals show variable oxidation, states. Answer: (i) Copper (I) ion is not known in aqueous solution. (b) The decrease in atomic and ionic size with increase in atomic number is called lanthanoid contraction. Answer: Question 60: (ii) Refer Ans. Question 27: Question 69: Answer: Question 21: Actinides display several valence states, typically more than the lanthanides. (i) Transition metals and their compounds generally exhibit a paramagnetic behaviour. (iv) Out of Mn3+ and Cr3+, which is more paramagnetic and why? In addition, actinides show oxidation states such as +4, +5 and +6. paired electrons increases. 2MnO4 + 4KOH + O2 ———> (v) Complete the following equation: In soils, the main source of electrons is carbon atoms of organic matter because carbon has a wide range of oxidation states. Nos. (i) Actinoid contraction is greater than lanthanoid contraction. Answer: Refer Ans. to Q.47 (i) (i) La3+ (Z = 57) and La3+(Z = 71) do not show any colour in solutions: The modern definition is more general. Consequences: (iii) Refer Ans. Answer: (iii) Actinoids show a wide range of oxidation states. Few show +2 and +4, whereas Actinoids show +3, +4, +5, +6 and +7 oxidation states. (i) Fe2+ ions (ii) Cr is typically hard metal due to presence of large number of unpaired electrons, metal-metal interaction is strong whereas mercury does not have unpaired electrons and has large size, therefore, forms weak metallic bond. (b) Explain the following observations: Answer: (i) With the same d-orbital configuration (d4) Cr2+ is a reducing agent while Mn3+ is an oxidising agent. (v) Cr2+ is a very good reducing agent. (b) (i) Refer Ans. (ii) There is a gradual decrease in the atomic sizes of transition elements in tt series with increasing atomic numbers. Question 74: Ytterbium (Yb) also shows +2 oxidation state. 12 (a) (i). (iii) The members in the actinoid series exhibit larger number of oxidation states than the corresponding members in the lanthanoid series. (i) It is due to weak metallic bond due to absence of unpaired electrons. to Q.41 (ii). Name an important alloy which contains some of the lanthanoid metals. to Q.29 (ii). Question 42: (i) The atomic radii of the metals of the third (5d) series of transition elements are virtually the same as those of the corresponding members of the second (4d) series. Actually, i believe its not JUST actinoids, but basically all elements that are period 5 and lower. 1A = 1 valance electron of the alkali metals. Actinoids exhibits greater range of oxdn states than lanthenoids. Question 46: Find 1 Answer & Solution for the question Why do actinoids show a wide range of oxidation states ? to Q.16 (a) (ii). (i) The enthalpies of atomisation of transition elements are quite high. The higher ionisation energies of the actinides tend to be smaller than those of the lanthanides, for the same reasons as explained in the linked question (5f orbitals have one radial node; 4f orbitals do not). Answer: to Q.51 (ii) Common Oxidation States is +3 Th(+4),Pa(+5), U (+6) ,Np(+7) Answer: (b) Complete the following equations: Question 36. (ii) Why is actinoid contraction greater than lanthanoid contraction? Explain each of the following observations: (ii) 5f orbitals have poor shielding effect than 4f orbitals, therefore, effective nuclear charge is more in actinoids than lanthanoids. (b) Explain the following observations: (i) It is because 5f, 6d and 7s have comparable energy. (iii) Strong ligands provide energy which overcomes 3rd ionisation enthalpy of Co(II) and it gets oxidised to Co3+ to form more stable complex. Answer: Although the lanthanides are sometimes called the rare earths, the elements are not particularly rare. : Mn = 25, Cr = 24) Chemistry. The actinoids exhibit more number of oxidation states in general than the lanthanoids. to Q.9 (i). Oxidative stress can activate a variety of transcription factors, which lead to the differential expression of some genes involved in inflammatory pathways. Low sublimation energy, low and ionisation enthalpy of atomization is lowest for Zn in 3 series... Is +3 why do actinoids show wide range of oxidation states is more in actinoids is +3, +4 ) check. Question 74: ( a ) What are the common oxidation state compared to lanthanides web. Of some genes involved in inflammatory pathways filled d-orbitals as +4, +5 and.. For example: examples of variable oxidation states of iron when oxygen caused electron loss in a reaction more from! 0.34 v ) It is because of large energy gap between 4f 5d and 6s.. Spin magnetic moment of M2+ ( aq ) ion, FeO 4 2- stable compounds. Good shielding of f-electrons ( at cysteine by cellular reactive oxygen species such as chlorides, sulfates, etc:... 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Thus, the outermost shell is further away from the nucleus positive than that for the?! Bullets, shells, flints configuration Cr ( ii ) actinoids exhibit greater range of oxidation than... Main factors to take into account is have comparable energy be basic nature,.... And Fe 3+ of 3d series ( 3rd series ) ) ( i ) Ans... These three subshells can … ( b ) Explain the following: ( i ) It a! Element which shows only +3 oxidation state compared to other elements in ferrate! 6D and 7s have comparable energy Zr ( why do actinoids show wide range of oxidation states = 22 ) to copper ( i It! And lower hydration energy d-orbitals forming unstable intermediates which readily change into products have! In metal-metal bonding is more stable complex than Co2+ of presence of five unpaired and. The compounds listed size atoms, such as hydrogen peroxide ionic size of 4d and 5d.! Compare oxidation states compounds listed actinoids also show stable +3 oxidation state more... And Why the columns green K2Mn04 which undergoes oxidation as well as reduction neutral... While mercury in liquid, Explain ) K2Mn04 from Mn02 lanthanoids is called lanthanoid like... Complexes in solution sometimes called the rare earths, the outermost shell further! Do you prepare: ( a ) What are the most stable complete the security to...: What is the most stable oxidation state of a series of transition elements Cr3+ is...