MCQ
The lanthanide contraction is responsible for the fact that
- A$Zr$ and $Y$ have about the same radius
- B$Zr$ and $Nb$ have similar oxidation state
- ✓$Zr$ and $Hf$ have about the same radius
- D$Zr$ and $Zn$ have the same oxidation sate
✓
Answer
Correct option: C.
$Zr$ and $Hf$ have about the same radius
c
Due to lanthanide contration the size for $Zr$ and $Hf$ is same. Lanthanide contraction can be explained on the basis of shielding effect.In multi-electron atoms the electrons are added in outer shells. The electrons already present in inner shells, shield the outer electrons from nuclear charge, making them experience a lower effective charge of the nucleus. The shielding effect exerted by the inner electrons decreases in the order $s > p > d > f$. This $f$ subshell poorly shields the outer electron from nuclear attraction which results in more attractive pull of nucleus on outer electron and smaller size.In case of post lanthenide elements like $Hf , 4 f$ subshell is filled and it is not very effective at shielding the outer shell $(n=5$ and $n=6)$ electrons. it is similar to $Zr$.
Due to lanthanide contration the size for $Zr$ and $Hf$ is same. Lanthanide contraction can be explained on the basis of shielding effect.In multi-electron atoms the electrons are added in outer shells. The electrons already present in inner shells, shield the outer electrons from nuclear charge, making them experience a lower effective charge of the nucleus. The shielding effect exerted by the inner electrons decreases in the order $s > p > d > f$. This $f$ subshell poorly shields the outer electron from nuclear attraction which results in more attractive pull of nucleus on outer electron and smaller size.In case of post lanthenide elements like $Hf , 4 f$ subshell is filled and it is not very effective at shielding the outer shell $(n=5$ and $n=6)$ electrons. it is similar to $Zr$.
Need a full question paper?
Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.
Explore more
Similar questions
Which of the following sets of reagents, used in the order shown, would successfully accomplish the conversion shown ?
$\begin{matrix}
OH\,\, \\
|\,\,\,\,\,\,\, \\
C{{H}_{3}}-CH-C{{H}_{2}}- \\
\end{matrix}\begin{matrix}
O\,\,\,\,\, \\
||\,\,\,\,\,\, \\
C{{H}_{2}}-C-C{{H}_{3}}\to \\
\end{matrix}\begin{matrix}
OH\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\, \\
|\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\, \\
C{{H}_{3}}-CH-{{(C{{H}_{2}})}_{3}}-C{{H}_{3}} \\
\end{matrix}$
→OH\,\, \\
|\,\,\,\,\,\,\, \\
C{{H}_{3}}-CH-C{{H}_{2}}- \\
\end{matrix}\begin{matrix}
O\,\,\,\,\, \\
||\,\,\,\,\,\, \\
C{{H}_{2}}-C-C{{H}_{3}}\to \\
\end{matrix}\begin{matrix}
OH\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\, \\
|\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\, \\
C{{H}_{3}}-CH-{{(C{{H}_{2}})}_{3}}-C{{H}_{3}} \\
\end{matrix}$
Above conversion can be achieved by
The standard reduction potential values of the three metallic cations $x, y, z$ are $0.52\, V, -3.03\,V$ and $-1.18\,V$ respectively. The order of reducing power of their corresponding metals will be
→Biuret test is used for the detection of
$Zn$ and $Cd$ metals do not show variable valency because
→The correct order of reactivity of the halides$, (I)$ ethyl chloride$; (II)$ isopropyl chloride and $(\text{III})$ benzyl chloride in $SN_1$ reaction is:
→Neobium and tantalum metals are used in making surgical instruments because they are
Among the following nitrates, Lead nitrate, Silver nitrate and Ammonium nitrate; the one that decomposes without leaving any solid residue is
Which reagent cannot be used to prepare an alkyl halide from an alcohol
A solute $'A'$ undergoes association in a medium as $nA \rightleftharpoons {A_n}$. The degree of association is '$\alpha $' then van't hoff factor may be given as
→