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प्रश्न
Gadolinium belongs to 4f series. It’s atomic number is 64. Which of the following is the correct electronic configuration of gadolinium?
विकल्प
\[{[Xe] 4f^75d^16s^2}\]
\[{[Xe] 4f^65d^26s^2}\]
\[{[Xe] 4f^86d^2}\]
\[{[Xe] 4f^95d^1}\]
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उत्तर
\[{[Xe] 4f^75d^16s^2}\]
Explanation:
Gadolinium belongs to the 4f series; it has atomic no.= 64. It has extra stability due to a half-filled 4f subshell.
\[\ce{Gd (Z = 64) -> [Xe] 4f^6 5d^2 6s^2}\]
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संबंधित प्रश्न
Account for the following :
Zr and Hf have almost similar atomic radii.
Compare the chemistry of actinoids with that of the lanthanoids with special reference to atomic and ionic sizes.
Write the different oxidation states of iron
Explain, why lanthanum (Z = 57) forms La3+ ion, while cerium (Z = 58) forms Ce4+ ion?
Explain effects 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 meant by Lanthanide contraction? Write the general electronic configuration of inner transition elements.
What is lanthanoid contraction?
Although +3 is the characteristic oxidation state for lanthanoids but cerium also shows +4 oxidation state because:
(i) it has variable ionisation enthalpy
(ii) it has a tendency to attain noble gas configuration
(iii) it has a tendency to attain f 0 configuration
(iv) it resembles Pb4+
Although Zr belongs to 4d and Hf belongs to 5d transition series but it is quite difficult to separate them. Why?
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 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 |
The titanium (Z = 22) compound that does not exist is:-
In lanthanoid the last electron enters (n - 2)f subshell where n is equal to ______.
Write any two consequences of Lanthanoid Contraction.
Write a note on lanthanoids.
Why is Mn2+ ion more stable than Fe2+ ion?
(Atomic numbers of Mn = 25 and Fe = 26)
Assertion: There is a continuous increase in size among Lanthanoids with an increase in atomic number.
Reason: Lanthanoids do not show Lanthanoid contraction.
Name an important alloy which contains some of the lanthanoid metals. Mention its uses.
