Advertisements
Advertisements
प्रश्न
Why is the highest oxidation state of a metal exhibited in its oxide or fluoride only?
Advertisements
उत्तर
Due to its small size and high electronegativities, oxygen or fluorine elements can oxidize the metal to its higher oxidation state.
APPEARS IN
संबंधित प्रश्न
The elements of 3d transition series are given as: Sc Ti V Cr Mn Fe Co
Answer the following: Which element has the highest m.p?
Account for the following:
Cu+ ion is unstable in aqueous solution.
How would you account for the irregular variation of ionization enthalpies (first and second) in the first series of the transition elements?
How would you account for the following:
The d1 configuration is very unstable in ions.
Which metal in the first series of transition metals exhibits +1 oxidation state most frequently and why?
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 an aqueous solution?
Comment on the statement that elements of the first transition series possess many properties different from those of heavier transition elements.
How would you account for the following?
Transition metals and their compounds act as catalysts.
Dissociation of H2S is suppressed in acidic medium.
Why do transition metals exhibit higher enthalpy of atomization?
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.
When \[\ce{KMnO4}\] solution is added to oxalic acid solution, the decolourisation is slow in the beginning but becomes instantaneous after some time because ______.
Although \[\ce{Cr^3+}\] and \[\ce{Co^2+}\] ions have same number of unpaired electrons but the magnetic moment of \[\ce{Cr^3+}\] is 3.87 B.M. and that of \[\ce{Co^2+}\] is 4.87 B.M. Why?
Identify A to E and also explain the reactions involved.
Fill in the blanks by choosing the appropriate word(s) from those given in the brackets:
(activation energy, Threshold energy, increased, lowered, partially, full, d-d transition, Benzoic acid, benzaldehyde)
Only those transition metal ions will be coloured which have ______ filled d-orbitals facilitating ______.
Which of the following is non-metallic?
The complex showing a spin-span magnetic moment of 2.82 B.M. is :-
Give reasons for the following statement:
Zn, Cd, and Hg are soft metals.
The oxidation state of Fe in [Fe(CO)5] is ______.
The compounds of \[\ce{Ti^4+}\] ions are colourless due to ______.
