Advertisements
Advertisements
प्रश्न
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
Advertisements
उत्तर
- In every series, the first ionisation enthalpy generally increases gradually as we move from left to right, although some exceptions are observed in every series.
- In the same respective vertical column (group), the first ionisation enthalpy of some elements of the 4d series is higher, and that of some elements is lower as compared to the elements of the 3d series, although the first ionisation enthalpy of the 5d series is significantly higher as compared to the 3d and 4d series.
- The reason for this is the poor shielding effect of the 4f electrons in the 5d series (known as lanthanoid contraction), which increases the effective nuclear charge and binds the outermost electrons very tightly.
APPEARS IN
संबंधित प्रश्न
Explain why is Fe3+ more stable than Fe2+?
What may be the stable oxidation state of the transition element with the following d electron configuration in the ground state of its atom?
3d3
In what way is the electronic configuration of the transition elements different from that of the non-transition elements?
How is the variability in oxidation states of transition metals different from that of the non-transition metals? Illustrate with examples.
What can be inferred from the magnetic moment value of the following complex species?
| Example | Magnetic Moment (BM) |
| K2[MnCl4] | 5.9 |
Write the formula of an oxo-anion of Chromium (Cr) in which it shows the oxidation state equal to its group number
Why do transition metals exhibit higher enthalpy of atomization?
When \[\ce{KMnO4}\] solution is added to oxalic acid solution, the decolourisation is slow in the beginning but becomes instantaneous after some time because ______.
Match the properties given in Column I with the metals given in Column II.
| Column I (Property) | Column II (Metal) | |
| (i) | Element with highest second ionisation enthalpy |
(a) \[\ce{Co}\] |
| (ii) | Element with highest third ionisation enthalpy |
(b) \[\ce{Cr}\] |
| (iii) | \[\ce{M}\] in \[\ce{M(CO)6}\] is | (c) \[\ce{Cu}\] |
| (iv) | Element with highest heat of atomisation |
(d) \[\ce{Zn}\] |
| (e) \[\ce{Ni}\] |
Identify the metal and justify your answer.
Carbonyl \[\ce{M(CO)5}\]
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 standard electrode potentials of four elements A, B, C and D are – 3.05, – 1.66, – 0.40 and + 0.80. The highest chemical reactivity will be exhibited by
Sodium this sulphate is used in photography because of its:-
The value of Δ0 for \[\ce{RhCl^{3-}6}\] is 243 KJ/mol which wavelength of light will promote an electron from. The colour of the complex is ______.
The oxidation state of Fe in [Fe(CO)5] is ______.
Account for the following:
Ce4+ is a strong oxidising agent.
Write the number of unpaired electrons in Cr3+.
(Atomic number of Cr = 24)
What is the oxidation state of chromium in chromate ion and dichromate ion?
Decide which of the following atomic numbers are the atomic numbers of the inner transition elements:
29, 59, 74, 95, 102, 104
