1. Silver in its +1 oxidation state exhibits . Configuration but in some compounds is also shows +2 oxidation state so the configuration becomes here d - orbital is not completely filled therefore silver is a transition element. 2. Zinc has completely filled d- orbitals so not taking part in bonding. Thus metallic bond is weaker than the other elements of the series. In other elements of the series the electrons of d orbitals are involved in the formation of metallic bonds. So high enthalpy of atomization is observed. 3. Manganese show maximum number of oxidation states i.e. +2, +3, +4, +5, +6, +7 in its compounds due to maximum number of unpaired electrons. 4. value for any metal depend on three factors hydration enthalpy ionization enthalpy, enthalpy of atomization copper has high value of enthalpy of atomization and low value of hydration enthalpy and also the high energy to transform Cu(s) to is not balanced by its hydration enthalpy therefore it is positive. 5. compounds are more stable due to half filled d orbital’s compounds are comparatively less stable as they gave six electrons in their orbital so they tend to lose one electron (from ) and get stable 3d configuration 6. Due to lanthanoid contraction they have nearly similar size. 7. The electronic configuration of Zn Cd and Hg has completely filled orbitals in ground as well as in their common oxidation states +2 thus these are not considered as transition elements. 8. After losing fist electron Cr an Cu possess half filled an completely filled orbital’s respectively half filled and completely filled orbital’s have extra stability so it is difficult to remove second electron from it so second ionization enthalpy is unusually high. 9. Iron is used Haber’s process. 10. Hydration enthalpy of ion is more negative which is more than second ionization enthalpy of copper thus Cu (II) ion is stable in aqueous solution. 11. Self (Teacher) 12. Self (Teacher) 13. Self (Teacher) 14. Self (Teacher) 15. 16. It is dark purple colour (The deep purple colour of is due to charge transfer from O to Mn.) crystalline solid it is not very soluble in water (6.4 g / 100 g of H 2 O at 298 K) on heating it decomposes at 513 K an O 2 is evolved. 17. When dichromate ion is dissolved in alkali it forms chromate ion 18. (i) Bleaching of wool cotton silk and other textile filbres. (ii) Decolourisaion of oils. 19. Self (Teacher) 20. Self (Teacher) 21. Self (Teacher) 22. Three orbitals are incomplete in inner transition elements. 23. Due to the lanthanoids contraction atomic radii are identical. 24. Bullets. Shells, Lighter, Flint, are prepared by this alloy. 25. Lanthanum oxide. 26. Protactinium. 27. +3 is the most common oxidation state. 28. 95% iron, 5% carbon, Cr, Mn, Ni. 29. What are the different oxidation states exhibited by lanthanoids? 30. Self (Teacher) 31. Self (Teacher) 32. Self (Teacher) 33. Self (Teacher) 34. Self (Teacher) 35. Self (Teacher) 36. Self (Teacher) 37. Self (Teacher) 38. Self (Teacher) 39. Self (Teacher) 40. Self (Teacher) Generated From SaraNextGen App SaraNextGen.Com 0 10 s 5 d 4 0 9 s 5 d 4 ) s 4 , d 3 . C . E ( 2 5 Q E ) aq ( Cu 2+ + 2 Mn + 2 Fe + 3 Fe 5 + 2 Cu 4 KMnO 2 2 4 2 4 O MnO MnO K KMnO 2 + + ¾® ¾ O H CrO 2 OH 2 O Cr 2 2 4 2 7 2 + ¾® ¾ + - - -
Transcript
1. Silver in its +1 oxidation state exhibits .Configuration but in some compounds is also shows +2oxidation state so the configuration becomes
here d - orbital is not completely filled thereforesilver is a transition element.
2. Zinc has completely filled d- orbitals so not taking part inbonding. Thus metallic bond is weaker than the otherelements of the series. In other elements of the seriesthe electrons of d orbitals are involved in the formationof metallic bonds. So high enthalpy of atomization isobserved.
3. Manganese show maximum number of oxidation statesi.e. +2, +3, +4, +5, +6, +7 in its compounds
due to maximum number of unpaired electrons.4. value for any metal depend on three factors
hydration enthalpy ionization enthalpy, enthalpy ofatomization copper has high value of enthalpy ofatomization and low value of hydration enthalpy andalso the high energy to transform Cu(s) to isnot balanced by its hydration enthalpy therefore it ispositive.
5. compounds are more stable due to half filled dorbital’s compounds are comparatively less stableas they gave six electrons in their orbital so they tend tolose one electron (from ) and get stable3d configuration
6. Due to lanthanoid contraction they have nearly similarsize.
7. The electronic configuration of Zn Cd and Hg hascompletely filled orbitals in ground as well as in theircommon oxidation states +2 thus these are notconsidered as transition elements.
8. After losing fist electron Cr an Cu possess half filled ancompletely filled orbital’s respectively half filled andcompletely filled orbital’s have extra stability so it isdifficult to remove second electron from it so secondionization enthalpy is unusually high.
9. Iron is used Haber’s process.10. Hydration enthalpy of ion is more negative which
is more than second ionization enthalpy of copper thusCu (II) ion is stable in aqueous solution.
11. Self (Teacher)12. Self (Teacher)
13. Self (Teacher)14. Self (Teacher)15.
16. It is dark purple colour (The deep purple colour ofis due to charge transfer from O to Mn.)
crystalline solid it is not very soluble in water (6.4 g / 100g of H2O at 298 K) on heating it decomposes at 513 K anO2 is evolved.
17. When dichromate ion is dissolved in alkali it formschromate ion
18. (i) Bleaching of wool cotton silk and other textile filbres.(ii) Decolourisaion of oils.
19. Self (Teacher)20. Self (Teacher)21. Self (Teacher)22. Three orbitals are incomplete in inner transition
elements.23. Due to the lanthanoids contraction atomic radii are
identical.24. Bullets. Shells, Lighter, Flint, are prepared by this alloy.25. Lanthanum oxide.26. Protactinium.27. +3 is the most common oxidation state.28. 95% iron, 5% carbon, Cr, Mn, Ni.29. What are the different oxidation states exhibited by
: nickel : oxidation states +2: such configuration does not exist in ground state.
56. ; Group number = oxidation state of Sc = 3; Group number = oxidation state of Ti = 4
; Group number = oxidation state of V = 5; Group number = oxidation state of Cr = 6
; Group number = oxidation state of Cr = 6; Group number = oxidation of state of Mn = 7
57. Elements (+2 state)and the electronic
configuration are respectively.In all elements listed the removal of two 4s electrons (in
1 from 4s and From 3d) the 3d orbital’s getgradually occupied since the number of empty d-orbital’s decrease or the number of unpaired electronsin 3d orbital’s increase with increase in atomic numberof cations so the stability of the cation increasefrom .
58. If orbital is half filled or completely filled it impartsstability to an atom or ion.e.g. (1)
e.g. (ii)
In manganese ion is more stable due to symmetryand half filled d orbitals in the same way in copper
ion is more stable due to symmetry and completelyfilled orbitals.
59. Oxygen and fluorine both have small size and high valueof electro negativity so they can oxidize the metal totheir higher oxidation states.
60. is stronger reducing agent.From
FromIn a medium (e.g. water) is more stable incompression to .
61. The electronic configuration ofhere M is Ni the outer configuration of
means three unpaired electrons are presentin an ion so spin only magnetic moment.
62. In aqueous solution copper (I) undergoes disproportionnation reaction.
The highest stability of ion in aqueous solution isdue to negative enthalpy of hydration.
63. Transition elements has incomplete d orbitals i.e. theirelectronic configuration is in nontransition elements d orbitals is absent or completelyfilled and they have type electronicconfiguration.
64. The compounds in which small atoms like H, C, N etc.occupy intestinal sites in the crystal lattice are calledinterstitial compounds. These compounds are wellknown for transition metals because small atoms caneasily occupy by the position in the voids present in thecrystal lattices of transition metals.
65. In transition elements the oxidation states vary by unity(due to incomplete filling of d orbital) e.g. Nn exhibits +2,+3, +4, +5, +6 and +7 all differing by 1.In non transition elements this variation is selectivealways differing by 2 e.g. S exhibits 2, 4, 6 oxidationstates N exhibits 3, 5 etc.
66. (i) is a negative (-0.4 V) it shows thestability of ions i.e. in solution cannot bereduced to ions further has high positivevale so it is easily converted to as compare tothe conversion of thus is the morestable than but less stable than(ii) From the values the order of oxidation of themetal to lthe divalent cation is Mn>Cr>Fe.
67. Electronic configuration of Cu = [Ar]3d104s1. Whencopper atom loses 1 electron it exhibits +1 oxidationstate and forms ion with stable configurationso copper metal in the first transition series tends tohave +1 oxidation state to achieve a stable configuration
68. (i) Transition elements exhibit colour due to d-dtransition structure defects and charge transferelectrons of lower energy level of d- orbitals absorbenergy from visible region for excitation to higher level.(ii) Zn has completely filled d- orbital in its ground stateas well as in its common oxidation state. Hence Zn notregarded as a transition elements.
69. It can be explained on the basis of strong inter atomicinteraction due to unpaired electrons greater is thenumber of unpaired electrons stronger is the resultantbonding.Metals of second and third series have high enthalpy ofatomization because of stronger metal- metal bond.
70. The electron is being removed from ion of iron andall other subsequent members of the series. Thiselectron is coming from d- orbitals so electron repulsionassists removal.
76. Potassium permanganates prepared by pyrolusiteore. When pyrolusite ore is fused with alkali in
the presence of air or an oxidizing agent likepotassium permanganate is formed.
77. On the large scale is prepared by alkalineoxidative fusion of followed by electrolyticoxidation of magnate (VI).
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isM27
,s4d3]Ar[ 27
72 d3isNi +
BM87.3)23(3)2n(n =+=+=m
)s(CuCu)aq(Cu2 2 +¾®¾ ++
+2Cu
.nsd)1n( 21101 ---
61221 npnsorns --
)Cr/Cr(E 230 ++
+3Cr +3Cr+2Cr +3Mn
0E +2Mn++ 23 FeandFe 3Cr
+3Mn +3Cr0E
+Cu 10d3
+2M
2423223242 CO8CrONa8OFe2O7CONa8OFeCr4 ++¾®¾++
OHNa2OCrNaH2CrONa2 272242++ +¾®¾+
NaCl2OCrKKCl2OCrNa 722722 +¾®¾+
)MnO( 2
3KNO
magnatepotassiumOH2MnOK2OKOH4MnO2 24222 +¾®¾++
4KMnO
2MnO
OH2MnOK2OKOH4MnO2 24222 +¾®¾++--- +¾®¾ eMnOMnO 4
24
78. Potassium dichromate is a strong oxidizing agent , inacidic solution its oxidizing action may be represented as
Ionic equations(i) Reaction of
(ii) Reaction of with
(iii) Reaction of
79. (i) When chromite ore is fused with sodium potassiumcarbonate in free access of air.
(ii) Potassium permanganates prepared by pyrolusiteore. When pyrolusite ore is fused with alkali in
the presence of air or an oxidizing agent likepotassium permanganate is formed.
80. (i) Acidified potassium dichromate oxidises iron (II) Saltin iron (III).
(ii) In neutral aqueous medium thiosulphate is oxidizedto sulphate.
81. Potassium magnate is of green colour whichdisproportionate in a neutral or acidic solution toproduce potassium permanganate.
(ii)
82. Self (Teacher)83. Self (Teacher)84. The decrease in atomic (or ionic) radii in actinoid
elements (actinoid contraction ) is greater thanlanthanoid contraction because 5f- electrons have poorshielding effect as compared to 4f- electrons thereforethe effect of increased nuclear charge leading tocontraction in size is more is case of actinoid elements.
85. Ce (Z = 58) =(only unpaired electron) i.e. n = 1 by spin
only formula,Magnetic moment of since n =
1(unpaired electron) =
86. +4 oxidation states exists in
+2 oxidation states exists in
Generally +2 oxidation state is exhibited by the elementswith configuration so that two electrons may beeasily lost. Similarly +4 oxidation state is shown by theelements which after losing four electrons acquireconfiguration either close to
87. Lanthanoids show limited number or oxidation states,i.e. +2, +3 and +4 (+3 is most common) this is due to thelarge energy gap between 5d and 6s sub shells whileactionoids show +3 oxidation state in general.There is a greater range of oxidation states varying from+3 to +7 this variation is due to the fact that 5f, 6d and7s levels are of comparable energies due to unevendistribution of oxidation states among actinoidselements their study becomes somewhat difficult e.g.maximum oxidation state = +4 in Th, +5 in Pa +6 in U, +7in Np.
88. Promethium of Pm (Z = 61) =Promethium of Pm (Z = 91) =Promethium of Pm (Z = 101) =Promethium of Pm (Z = 109) =
103. Self (Teacher)104. Ionization enthalpy is generally high due to increase
in nuclear charge and small size for a particulartransition series ionization enthalpy increase generallyon moving from left to right. The relative difference ofionization enthalpies of any two succeive d- blockelements of particular period is much smaller than thereof s - and p block elements.The explanation is that the variation in ionizationenthalpy within the d- block is small due to thescreening effect and attractive force acting together.The lower valence state is ionic and the highest valencestate is covalent. Ionization enthalpy increase from leftto right is a series but irregularities are observed due toirregular trends in electronic configuration.In 3d series first four members how little difference inValues and last four are also fairly close Zn shows quitehigh value due to extra stability of completely filledorbital.There are a fall in from Cr to Mn and fromCu to Zn because after the removal of first electron Crand Cu acquire a stable configuration i.e. . Thehigh values of for Cu, Ni and Zn explain why theyshow a maximum oxidation state of +2.
105. (i) Value of is negative (- 0.41 V)while that of is positive (+1.57) this meansthat ions can be lose electrons to from ionscan accept electrons and can act as an oxidizing agent.(ii) Cobalt (III) ion has greater tendency to formcomplexes than cobalt (II) ion. Therefore Co (II) ionbeing stable in aqueous solution changes to Co (III) ionin the presence of complexion reagents and getsoxidized.(iii) Ions of transition metals with configuration tendto los one electron to acquire configuration that isquite stable. Therefore such ions (with ) undergoeither with oxidation or disproportionation henceunstable.
106.
is the most stable among these in aqueous solutionbecause it ahs half filled .
107. (i) Acidic strength of oxides increases with theincrease in oxidation state of the elements e.g.
is basic whereas is acidic innature.(ii) Both oxygen and fluorine being highly electronegative can increase the oxidation state of a particulartransition metal in certain oxides the element oxygen itsinvolved in multiple bonding with the metal and this isresponsible for the higher oxidation state of the metal.(iii) This is also due to high electro negativity of oxygene.g. chromium exhibits oxidation state of +6 in oxoanian
and manganese shows oxidation state of +7 inoxoanian
108. (i) The atomic radii of the third series of transitionelements are virtually the same as those of thecorresponding members of the second series because oflanthanoids contraction.(ii) is less stable than which havestable half filled configuration is more stable than
due to half filled configuration. has stableconfiguration so value for the
couple is much more positive.(iii) Due to high electro negativity and small sizes ofoxygen an fluorine.
112. is prepared by treating the solution ofwith KCl because sodium dichromate is more
soluble than potassium dichromate.
Effect of increasing solution.
On increasing pH changes into
113. When a particular oxidation state becomes lessstable relative to other oxidation states i.e. one lowerone higher it is said to undergo disproportionation.e.g.(i) Mn (VI) becomes unstable relative to Mn (VII) and Mn(IV) in acidic solution.
(ii) Many Cu (I) compounds are unstable in aqueoussolution and undergo disproportion as follows.
114. (i) The composition of stainless steel is iron carbonnickel and chromium.(ii) Because potassium permanganate is disinfectant(iii) Values associated with the act of Yathartha(a) Care and concern(b) Responsible attitude(c) Hygiene(d) Awareness(e) Applied theoretical knowledge to daily life situation(f) Scientific attitude.
Oxidation state (s) Oxidation state (s)Most commonoxidation state = +3
Most commonoxidation state = +3
Other oxidation state =+2, +4
Other oxidation state =+4, +5, +6 and +7
Chemical reactivity Chemical reactivityLess tendency towardscomplex formation
Stronger tendencytowards complexformation
Except promethiumthey are nonradioactive
They are radioactive
They do not formoxocations
They form oxocations
Oxides and hydroxideare less basic
Oxides and hydroxideare more basic
118. (i) Alloys: An alloy is a homogeneous mixture of twoor more metals or non metals. It is prepared by lendingthe metals (and/ or non metal) in molten state.(ii) An important alloy containing lanthanides metal (-95%) iron (- 5%) traces of S, C, Ca and Al is mischmetall.
(iii) Mischmetall is used in Mg bases alloy to producebullets shell and lighter flint.
119. Lawrencium (Lr, Z = 103) is the last elements ofactinoids series.ConfigurationIts possible oxidation state = +3.
128. Self (Teacher)129. The Sum IE1 + IE2 increases. As a result, the standard
reduction potentials (E0) becomes less and less negative.Hence, the tendency to form M2+ ion decreases. Thegreater stability of +2 state for Mn is due to half-filledd-subshell (3ds). So, the first member of teh firsttransitions series is having electronic configurations of3d1 4s2 . It will prefer to lose all the three electrons tofrom Argon core. Therefore, it prefers to show anoxidation state of + 3 more than + 2.
130. The most stable oxidations state for 3d3 4s2 is + 5.(3d0) +3 and + 4.
The most stable ox. State for 3d5 4s1 = + 6 (3d0) and also1 + 3 and +4.The most stable ox. State for 3d5 4s2 = +2, +7 (3d0, 3d0)and also + 4 and +6.The most stable ox. State for 3d0 4s2 = +2The most stable ox. State for 3d4 there is no d+
configurations in ground state.The maximum oxidations states of reasonable stabilitycorrespond to the sum of a and d-electrons upto Mn.After that, there is abrupt decrease in the stability fohigher oxidations states.
131. (i) dichromate ion (Cr2O72-) and chromate ion (CrO4
2-)in oxidations state of Cr is VI and its group No. also 6.
(ii) MnO4- : Permanganate ion. Here ox. State of Mn is
VII and its group no is 7.(iii) Vandate : VO3
-; Here ox. No. of V=+5= group No. 5
132.
133.
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134.
135. This is because Pt4+ is more stable than Ni4+ as thesum of 4IE’s of Pt is less than that of Ni.
136. In the 5d series, after lanthanum (Z=57), there islanthanide contractions. In each group the size of the 5delement is smaller while nuclear charge is greater than3d element. Hence ionisations energies of 5d elementsare greater than 3d elements.
162. (i) In CuCl, has fully filled d-subshell. It canundergo d-d transition. Therefore, it is colourless. In
, has configuration. Due to thepresence of one half-filled d-orbital, it can absorb for d-dtransition. Hence, it is coloured.(ii) has one electron in d-subshell. It canundergo d-d transition by absorbing a part of visible light.On the other hand, has no electron ind-subshell. It cannot undergo d-d transition.
221. (i) Electronic configuration: The elements in thesame vertical column generally have similar electronicconfiguration although the first series has only twoexceptions.
Second transition series have fie exceptions
Third transition series has three exceptions.
(ii) Oxidation states: The elements in the same verticalcolumn generally show similar oxidation state thenumber of oxidation states shown by the elements s inthe middle of each series in maximum and minimum atthe extreme ends.(iii) Ionization enthalpies: The first ionization enthalpiesin each series generally increase gradually as we movefrom left to right. Through some exceptions areobserved in each series. The first ionization enthalpies ofsome elements in the second (4d) series are higherwhile some of them have lower value than the elementsof 3d series in the same vertical column.
(iv) Atomic size: Generally ions of the same charge oratoms in a given series show progressive decrease inradius with increasing atomic number through thedecrease is quite small. But eh size of the atom of the 4d series is larger than the corresponding elements of the3d series whereas those of corresponding elements ofthe 5d series are nearly the same as those of 4d seriesdue to lanthanoid concentration.
