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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:
Atomic sizes
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उत्तर
- Generally, ions or atoms of the same charge in a series show a gradual decrease in radius with increasing atomic number, although this decrease is very small.
- But the size of the atoms of the 4d series is larger than the corresponding elements of the 3d series, while the size of the corresponding elements of the 5d series is almost the same. The reason for this is lanthanoid contraction.
संबंधित प्रश्न
Why is Sc3+ colourless while Ti3+ coloured? (Atomic number Sc = 21, Ti =22)
Explain why is Fe3+ more stable than Fe2+?
The elements of 3d transition series are given as: Sc Ti V Cr Mn Fe Co
Answer the following: Which element is a strong oxidising agent in +3 oxidation state and why?
Give reasons:
Transition metals show variable oxidation states.
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?
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?
When acidified \[\ce{K2Cr2O7}\] solution is added to \[\ce{Sn^{2+}}\] salts then \[\ce{Sn^{2+}}\] changes to ______.
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?
Assertion: \[\ce{Cu^2+}\] iodide is not known.
Reason: \[\ce{Cu^2+}\] oxidises \[\ce{I^-}\] to iodine.
Identify the metal and justify your answer.
\[\ce{MO3F}\]
The element with atomic number 53 belongs to
Which of the following is non-metallic?
Which of the following ions has the maximum magnetic moment?
Match List - I with List - II.
| List - I | List - II | ||
| (A) | [Fe(CN)6]3− | (i) | 5.92 BM |
| (B) | [Fe(H2O)6]3+ | (ii) | 0 BM |
| (C) | [Fe(CN)6]4− | (iii) | 4.90 BM |
| (D) | [Fe(H2O)6]2+ | (iv) | 1.73 BM |
Choose the correct answer from the options given below.
Give reason for the following statement:
[Ti(H2O)]3+ is coloured while [Sc(H2O)6]3+ is colourless.
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?
A transition element X has an electronic configuration [Ar]4s23d3. Predict its likely oxidation states.
What is the oxidation state of chromium in chromate ion and dichromate ion?
Describe the oxidising action of potassium dichromate and write the ionic equation for its reaction with iron (II) solution.
