Advertisements
Advertisements
प्रश्न
Name the members of the lanthanoid series which exhibit +4 oxidation state and those which exhibit +2 oxidation state. Try to correlate this type of behavior with the electronic configurations of these elements.
Advertisements
उत्तर १
The lanthanides that exhibit +2 and +4 states are shown in the given table. The atomic numbers of the elements are given in parentheses.
| +2 | +4 |
| Nd (60) | Ce (58) |
| Sm (62) | Pr (59) |
| Eu (63) | Nd (60) |
| Tm (69) | Tb (65) |
| Yb (70) | Dy (66) |
After forming Ce4+, Ce attains a stable electronic configuration of [Xe].
After forming Tb4+, Tb attains a stable electronic configuration of [Xe] 4f7.
After forming Eu2+, Eu attains a stable electronic configuration of [Xe] 4f7.
After forming Yb2+, Yb attains a stable electronic configuration of [Xe] 4f14.
उत्तर २
All lanthanoids show the Ln3+ oxidation state. But some of them also show +2 and +4 states in solution and solid forms, such as Ce4+, Eu2+, Yb2+, Tb4+, etc. The changing oxidation state correlates with electronic configuration owing to the enhanced stability of half-filled, fully filled, or vacant orbitals. e.g., Ce4+ has 4f0, Eu2+ has 4f7, Tb4+ has 4f7, and Yb2+ has 4f4 configuration.
APPEARS IN
संबंधित प्रश्न
What are lanthanoids?
What are the different oxidation states exhibited by the lanthanoids?
Write the different oxidation states of iron
What are the consequences of lanthanoid contraction?
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 the action of the following on lanthanoids?
a. water
b. Sulphur, heat
c. nitrogen, heat
The f-block elements are known as ____________.
Match the compounds/elements given in Column I with uses given in Column II.
| Column I (Compound/element) | Column II (Use) | |
| (i) | Lanthanoid oxide | (a) Production of iron alloy |
| (ii) | Lanthanoid | (b) Television screen |
| (iii) | Misch metal | (c) Petroleum cracking |
| (iv) | Magnesium based alloy is constituent of | (d) Lanthanoid metal + iron |
| (v) | Mixed oxides of lanthanoids are employed | (e) Bullets |
| (f) In X-ray screen |
Match the statements given in Column I with the oxidation states given in Column II.
| Column I | Column II | |
| (i) | Oxidation state of Mn in MnO2 is | (a) + 2 |
| (ii) | Most stable oxidation state of Mn is | (b) + 3 |
| (iii) | Most stable oxidation state of | (c) + 4 |
| Mn in oxides is | (d) + 5 | |
| (iv) | Characteristic oxidation state of lanthanoids is | (e) + 7 |
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:
Nature of bonding in \[\ce{La2O3}\] and \[\ce{Lu2O3}\] .
On the basis of Lanthanoid contraction, explain the following:
Trends in the stability of oxo salts of lanthanoids from \[\ce{La}\] to \[\ce{Lu}\].
Which of the following pairs has the same ionic size?
The titanium (Z = 22) compound that does not exist is:-
The lathanide ion that would show colour is ______.
Why is Mn2+ ion more stable than Fe2+ ion?
(Atomic numbers of Mn = 25 and Fe = 26)
Trivalent Lanthanoid ions such as La3+ (Z = 57) and Lu3+ (Z = 71) do not show any colour in their solution. Give a reason.
Assertion: There is a continuous increase in size among Lanthanoids with an increase in atomic number.
Reason: Lanthanoids do not show Lanthanoid contraction.
