Advertisements
Advertisements
प्रश्न
On the basis of Lanthanoid contraction, explain the following:
Radii of 4d and 5d block elements.
Advertisements
उत्तर
As an effect of lanthanide contraction, zirconium and hafnium have similar radius of 160 pm and 159 pm respectively. Due to this similarity in their size, they show similar physical and chemical properties. Lanthanoid contraction: Because the elements in Row 3 have 4f electrons. These electrons do not shield good, causing a greater nuclear charge. This greater nuclear charge has a greater pull on the electrons and result in the decrease in their size and atomic radii.
APPEARS IN
संबंधित प्रश्न
Account for the following :
Zr and Hf have almost similar atomic radii.
Name a member of the lanthanoid series which is well known to exhibit +4 oxidation state.
Compare the chemistry of actinoids with that of lanthanoids with special reference to electronic configuration.
Explain the cause of Lanthanoids contraction.
Which trivalent ion has the maximum size in the Lanthanoid series, i.e., Lanthanum ion (La3+) to Luteium ion (Lu3+)?
(at. no. of Lanthanum = 57 and Lutetium = 71)
Name an element of lanthanoid series which is well knwon to shown +4 oxidation state. Is it a strong oxidising agent or reducing agent?
What is Lanthanoid contraction?
Although +3 oxidation states is the characteristic oxidation state of lanthanoids but cerium shows +4 oxidation state also. Why?
Match the property given in Column I with the element given in Column II.
| Column I (Property) | Column II (Element) | |
| (i) | Lanthanoid which shows +4 oxidation state |
(a) Pm |
| (ii) | Lanthanoid which can show +2 oxidation state |
(b) Ce |
| (iii) | Radioactive lanthanoid | (c) Lu |
| (iv) | Lanthanoid which has 4f7 electronic configuration in +3 oxidation state |
(d) Eu |
| (v) | Lanthanoid which has 4f14 electronic configuration in +3 oxidation state |
(e) Gd |
| (f) Dy |
On the basis of Lanthanoid contraction, explain the following:
Trends in the stability of oxo salts of lanthanoids from \[\ce{La}\] to \[\ce{Lu}\].
On the basis of Lanthanoid contraction, explain the following:
Trends in acidic character of lanthanoid oxides.
Which of the following pairs has the same ionic size?
Zr (Z = 40) and Hf (Z = 72) have similar atomic and ionic radii because of ______.
The lathanide ion that would show colour is ______.
Mischmetal is an alloy consisting mainly of ______.
State a reason for the following:
La(OH)3 is more basic than Lu(OH)3.
Trivalent Lanthanoid ions such as La3+ (Z = 57) and Lu3+ (Z = 71) do not show any colour in their solution. Give a reason.
