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.
APPEARS IN
संबंधित प्रश्न
Why do interstitial compounds have higher melting points than corresponding pure metals?
How is the variability in oxidation states of transition metals different from that of the non-transition metals? Illustrate with examples.
An analysis shows that FeO has a non-stoichiometric composition with formula Fe0.95O. Give reason.
The paramagnetic character in the 3d-transition series elements increases up to Mn and then decreases.
\[\ce{KMnO4}\] acts as an oxidising agent in acidic medium. The number of moles of \[\ce{KMnO4}\] that will be needed to react with one mole of sulphide ions in acidic solution is ______.
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) \[\ce{Cr^{3+}}\]
Transition elements form binary compounds with halogens. Which of the following elements will form \[\ce{MF3}\] type compounds?
(i) \[\ce{Cr}\]
(ii) \[\ce{Co}\]
(iii) \[\ce{Cu}\]
(iv) \[\ce{Ni}\]
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 ______.
The element with atomic number 46 belongs to
The orientation of an atomic orbital is governed by
Photographic film and plates have - au essential ingredient of
The electrode potential of M2+/M of 3d-series elements shows the positive value for ______.
Consider the following standard electrode potentials (E° in volts) in aqueous solution:
| Element | M3+/M | M+/M |
| Al | - 1.66 | +0.55 |
| Tl | + 1.26 | -0.34 |
Based on these data, which of the following statements is correct?
In the ground state of atomic Fe (Z = 26), the spin-only magnetic moment is ______ × 10-1 BM.
(Round off to the nearest integer).
[Given: `sqrt3 = 1.73, sqrt2 = 1.41`]
The given graph shows the trends in melting points of transition metals:
Explain the reason why Cr has the highest melting point and manganese (Mn) has a lower melting point.
A pair of coloured ions is ______.
Describe the oxidising action of potassium dichromate and write the ionic equation for its reaction with H2S.
The E° value for the Mn2+/Mn2+ couple is more positive than that of Cr3+/Cr2+ or Fe3+/Fe2+ due to the change of:
