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प्रश्न
The halides of transition elements become more covalent with increasing oxidation state of the metal. Why?
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उत्तर
As the oxidation state of the element increases, its charge increases. To Fajans rules, as the charge of the metal ion increases covalent character increases because the positively charged cation attracts the electron cloud on the anion towards itself.
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संबंधित प्रश्न
Which of the following cations are coloured in aqueous solutions and why ?
Sc3+, V3+, Ti4+, Mn2+ (At. Nos. Sc = 21, V = 23, Ti = 22, Mn = 25)
The elements of 3d transition series are given as: Sc Ti V Cr Mn Fe Co
Answer the following: Which element shows only +3 oxidation state?
Account for the following:
Cu+ ion is unstable in aqueous solution.
Account for the following:
Zn is not considered as a transition element.
Explain why transition elements form alloys.
Which among the following transition metal has the lowest melting point?
Transition metals with highest melting point is ____________.
Read the passage given below and answer the following question:
The transition metals when exposed to oxygen at low and intermediate temperatures form thin, protective oxide films of up to some thousands of Angstroms in thickness. Transition metal oxides lie between the extremes of ionic and covalent binary compounds formed by elements from the left or right side of the periodic table. They range from metallic to semiconducting and deviate by both large and small degrees from stoichiometry. Since electron bonding levels are involved, the cations exist in various valence states and hence give rise to a large number of oxides. The crystal structures are often classified by considering a cubic or hexagonal close-packed lattice of one set of ions with the other set of ions filling the octahedral or tetrahedral interstices. The actual oxide structures, however, generally show departures from such regular arrays due in part to distortions caused by packing of ions of different size and to ligand field effects. These distortions depend not only on the number of d-electrons but also on the valence and the position of the transition metal in a period or group.
In the following questions, a statement of assertion followed by a statement of reason is given. Choose the correct answer out of the following choices on the basis of the above passage.
Assertion: Cations of transition elements occur in various valence states.
Reason: Large number of oxides of transition elements are possible.
Electronic configuration of a transition element X in +3 oxidation state is [Ar]3d5. What is its atomic number?
Metallic radii of some transition elements are given below. Which of these elements will have highest density?
| Element | \[\ce{Fe}\] | \[\ce{Co}\] | \[\ce{Ni}\] | \[\ce{Cu}\] |
| Metallic radii/pm | 126 | 125 | 125 | 128 |
Highest oxidation state of manganese in fluoride is \[\ce{+4 (MnF4)}\] but highest oxidation state in oxides is \[\ce{+7 (Mn2O7)}\] because ______.
EΘ of Cu is + 0.34V while that of Zn is – 0.76V. Explain.
Reactivity of transition elements decreases almost regularly from Sc to Cu. Explain.
Among the following pairs of ions, the lower oxidation state in aqueous solution is more stable than the other in:-
Agcl is soluble in NH4OH. The solubility is due to the information of:-
Which one among the following metals of the 3d series has the lowest melting point?
The trend of which property is represented by the following graph?
Compare the general characteristics of the first series of the transition metals with those of the second and third series metals in the respective vertical columns. Give special emphasis on the following point:
Ionisation enthalpies
The E° value for the Mn2+/Mn2+ couple is more positive than that of Cr3+/Cr2+ or Fe3+/Fe2+ due to the change of:
