Gadolinium belongs to 4f series. It’s atomic number is 64. Which of the following is the correct electronic configuration of gadolinium?
Assuming complete ionization, same moles of which of the following compounds will require the least amount of acidified KMnO4 for complex oxidation?
Because of lanthanoid contraction, which of the following pairs of elements have nearly the same atomic radii? (Numbers in the parenthesis are atomic numbers).
Which of the following processes does not involve the oxidation of iron?
|1.||Rusting of iron sheets|
|2.||Decolourisation of blue CuSO4
solution by iron
|3.||Formation of Fe(CO)5 from Fe|
|4.||Liberation of H2 from steam by
iron at high temperature
The pair of compounds that can exist together is:
1. FeCl3, SnCl2
2. HgCl, SnCl2
3. FeCl2, SnCl2
4. FeCl3, Kl
In acidic medium, H2O2 changes Cr2O7–2 to CrO5 which has two (–O – O–) bonds. The oxidation state of Cr in CrO5 is:
Reason of lanthanoid contraction is:
1. Negligible screening effect of 'f' orbitals
2. Increasing nuclear charge
3. Decreasing nuclear charge
4. Decreasing screening effect