Advertisements
Advertisements
प्रश्न
Transition elements show high melting points. Why?
Explain giving reasons:
Transition elements have higher melting and boiling points.
Why do transition elements have much higher melting points?
Advertisements
उत्तर १
The high melting points of transition metals are attributed to the involvement of greater number of electrons in the interatomic metallic bonding from (n – 1) d-orbitals in addition to ns electrons.
उत्तर २
- Transition elements have higher melting and boiling points because their atoms are held together by strong metallic bonds.
- These metallic bonds have significant covalent character due to the presence of unpaired d-electrons that overlap between atoms.
- More unpaired d-electrons mean more covalent bonding and stronger metallic bonds, which require more energy to break.
- The close-packed structures of transition metals also contribute to the strong bonding and thus high melting and boiling points.
- Melting and boiling points generally increase up to the middle of the series because the number of unpaired d-electrons also increases up to that point.
संबंधित प्रश्न
In the series Sc (Z = 21) to Zn (Z = 30), the enthalpy of atomization of zinc is the lowest, i.e., 126 kJ mol−1. Why?
How would you account for the following:
Cobalt (II) is stable in aqueous solutions, but in the presence of complexing reagents, it is easily oxidised.
Which metal in the first series of transition metals exhibits +1 oxidation state most frequently and why?
What are alloys?
What can be inferred from the magnetic moment value of the following complex species?
| Example | Magnetic Moment (BM) |
| K2[MnCl4] | 5.9 |
An analysis shows that FeO has a non-stoichiometric composition with formula Fe0.95O. Give reason.
Complete and balance the following chemical equations
`MnO_4^(-) + H_2O + I^(-) ->`
Why do transition metals exhibit higher enthalpy of atomization?
Explain why Zn2+ salts are white whereas Cu2+ salts are coloured.
Transition metals with highest melting point is ____________.
Why is \[\ce{HCl}\] not used to make the medium acidic in oxidation reactions of \[\ce{KMnO4}\] in acidic medium?
Transition elements show magnetic moment due to spin and orbital motion of electrons. Which of the following metallic ions have almost same spin only magnetic moment?
(i) \[\ce{Co^{2+}}\]
(ii) \[\ce{Cr^{2+}}\]
(iii) \[\ce{Mn^{2+}}\]
(iv) \[\ce{Cr^{3+}}\]
Match the catalysts given in Column I with the processes given in Column II.
| Column I (Catalyst) | Column II (Process) |
| (i) \[\ce{Ni}\] in the presence of hydrogen | (a) Zieglar Natta catalyst |
| (ii) \[\ce{Cu2C12}\] | (b) Contact process |
| (iii) \[\ce{V2O5}\] | (c) Vegetable oil to ghee |
| (iv) Finely divided iron | (d) Sandmeyer reaction |
| (v) \[\ce{TiCl4 + Al (CH3)3}\] | (e) Haber's Process |
| (f) Decomposition of KCIO3 |
The product of oxidation of I– with \[\ce{MnO^{-}4}\] in alkaline medium is:-
The basic character of transition metals monoxide follow the order.
Which of the following ions will exhibit colour in aqueous solution?
Give reason for the following statement:
[Ti(H2O)]3+ is coloured while [Sc(H2O)6]3+ is colourless.
Why Zn, Cd and Hg are not called transition metals?
Explain the use of different transition metals as catalysts.
The compounds of \[\ce{Ti^4+}\] ions are colourless due to ______.
