Metallic radii of some transition elements are given below. Which of these elements will have highest density?
(d) On moving left to right along period, metallic radius decreases while mass increases. Decreases in metallic radius coupled with increase in atomic mass results in increase in density of metal.
Hence, among the given four choices Cu belongs to right side of Periodic Table in transition metal, and it has the highest density (89 g/cm3).
Assertion (A): Cu can not libirate hydrogen from acids .
Reason (R): because it has positive electrode potential.
Actinoid contraction is greater from element to element than lanthanoid contraction. Why?
In the following questions, a statement of Assertion (A) followed by a statement of Reason (R) is given. Choose the correct answer out of the following choices:
(a) Both Assertion and Reason are true and the Reason is the correct explanation of Assertion.
(b) Both Assertion and Reason are true and the Reason is not the correct explanation of Assertion.
(c) Assertion is not true but the Reason is true.
(d) Both Assertion and Reason are false.
Assertion (A): Cu2+ iodide is not known.
Reason (R): Cu2+ oxidises I to iodine.
While filling up of electrons in the atomic orbitals, the 4s orbital is filled before the 3d-orbital but reverse happens during the ionization of the atom. Explain why?
What may be the stable oxidation state of the transition element with the following delectron configurations in the ground state of their atoms: 3d3,3d5, 3d8 and 3d4?
Calculate the number of unpaired electrons in the following gaseous ions : Mn3+, Cr3+, V3+ and Ti3+. Which one of these is the most stable in aqueous solution.
Although fluorine is more electronegative than oxygen, but the ability of oxygen to stabilize higher oxidation states exceeds that of fluorine. Why?
Assertion (A): The highest oxidation state of osmium is +8.
Reason (R): Osmium is a 5d-block element.
When a chromite ore (A) is fused with sodium carbonate in free excess of air and the product is dissolved in water, a yellow solution of compound (B) is obtained. After treatment of this yellow solution with sulphuric acid, compound (C) can be crystallized from the solution. When compound (C) is treated with KCl, orange crystals of compound (D) crystallise out. Identify A to D and also explain the reactions.
In the form of dichromate, Cr (VI) is a strong oxidizing agent in acidic medium but Mo (VI) in MoO3 and W (VI) in WO3 are not because
(a) Cr (VI) is more stable than Mo(VI) and W(VI)
(b) Mo(VI) and W(VI) are more stable than Cr(VI)
(c) higher oxidation states of heavier members of group-6 of transition series are more stable
(d) lower oxidation states of heavier members of group-6 of transition series are more stable
Although Zr belongs to 4d and Hf belongs to 5d transition series but it is quite difficult to separate them. Why?
In the series Sc (Z = 21) to Zn (Z = 30), the enthalpy of atomisation of zinc is the lowest, i.e., 126 kJ mol-1 . Why?
Explain giving reasons:
(i)Transition metals and many of their compounds show paramagnetic behaviour.
(ii)The enthalpies of atomisation of the transition metals are high.
(iii)The transition metals generally form coloured compounds.
(iv)Transition metals and their many compounds act as good catalyst
Silver atom has completely filled d orbitals (4d10) in its ground state. How can you say that it is a transition element?
Compare the chemistry of actinoids with that of lanthanoids with reference to:
(i) Electronic configuration
(ii) Oxidation states
(iii) Chemical reactivity
Which of the following will not act as oxidizing agents?
(a) CrO3 (b) MoO3(c) WO3 (d) CrO42-
(a) Transition metals can act as catalysts because these can change their oxidation state.
How does Fe(III) catalyse the reaction between iodide and persulphate ions?
(b) Mention any three processes where transition metals act as catalysts.
A violet compound of manganese (A) decomposes on heating to liberate oxygen and compounds (B) and (C) of manganese are formed. Compound (C) reacts with KOH in the presence of potassium nitrate to give compound (B). On heating compound (C) with cone. H2SO4 and NaCl, chlorine gas is liberated and a compound (D) of manganese along with other products is formed. Identify compounds A to D and also explain the reactions involved.
How would you account for the irregular variation of ionisation enthalpies (first and second) in the first series of the transition elements?
Compare the stability of +2 oxidation state for the elements of the first transition series.
Which of the following lanthanoids show +2 oxidation state besides the characteristic oxidation state +3 of lanthanoids?
(a) Ce (b) Eu (c) Yb (d) Ho
When a brown compound of manganese
(A) is treated with HCl, it gives a gas
(B) The gas taken in excess, reacts with NH3 to give an explosive compound
(C) Identify compounds A, B and C.
Mention the type of compounds formed when small atoms like H, C and N get trapped inside the crystal lattice of transition metals. Also give physical and chemical characteristics of these compounds.
Which of the 3d series of the transition metals exhibits the largest number of oxidation states and why?
What are interstitial compounds? Why are such compounds well known for transition metals?
Calculate the number of unpaired electrons in the following gaseous ions : Mn3+, Cr3+, V3+ and Ti3+. Which one of these is the most stable in aqueous solution.
What are inner transition elements? Decide which of the following atomic numbers are the atomic numbers of the inner transition elements: 29,59,74,95,102,104.
Generally, transition-elements and their salts are coloured due to the presence of unpaired electrons in metal ions. Which of the following compounds are coloured?
(a) kMnO4 (b) Ce(SO4)2 (c) TiCl4 (d) Cu2Cl2
General electronic configuration of actinoids is (n – 2)f1-14 (n – 1 )d0-2 ns2. Which of the following actinoids have one electron in 6d orbital?
(a) U (Atomic no. 92) (b) Np (Atomic no. 93)
(c) Pu (Atomic no. 94) (d) Am (Atomic no. 95)
While filling up of electrons in the atomic orbitals, the 4s orbital is filled before the 3d-orbital but reverse happens during the ionization of the atom. Explain why?
Assertion (A): The highest oxidation state of osmium is +8.
Reason (R): Osmium is a 5d-block element.
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.
Predict which of the following will be coloured in aqueous solution? Ti3+, V3+,Cu+, Sc3+, Mn2+, Fe3+ and Co2+ Give reasons for each.
Which metal in the first series of transition metals exhibits + 1 oxidation state most frequently and why?
Transition elements form binary compounds with halogens. Which of the following elements will form MF3 type compounds?
(a) Cr (b) Co (c) Cu (d) Ni
Although Cr3+ and CO2+ ions have same number of unpaired electrons but the magnetic moment of Cr3+ is 3.87 BM and that of CO2+ is 4.87 BM. Why?
(a) Answer the following questions:
(i) Which element of the first transition series has highest second ionization enthalpy?
(ii) Which element of the first transition series has highest third ionization enthalpy?
(iii) Which element of the first transition series has lowest enthalpy of atomization?
(b) Identify the metal and justify your answer:
(i) Carbonyl M(CO)5 (ii) MO3F
In what way is the electronic configuration of the transition elements different from that of the non transition elements?
Describe the preparation of potassium dichromate from iron chromite ore. What is the effect of increasing pH on a solution of potassium dichromate?
What is meant by disproportionation? Give two examples of disproportionation reaction in aqueous solution.
