The Lanthanoids

What is meschmetal?

Given below are two statement : one is labelled as Assertion A and the other is labelled as Reason R

Assertion A : $5\mathrm{f}$ electron can participate in bonding to a far greater extent than $4\mathrm{f}$ electrons

Reason R : $5\mathrm{f}$ orbitals are not as buried as $4\mathrm{f}$ orbitals

In the light of the above statements, choose the correct answer from the options given below

Strong reducing and oxidizing agents among the following , respectively, are

Zirconium ($\mathrm{Zr}$, Atomic number $40$) and Hafnium ($\mathrm{Hf}$, Atomic number $72$) are transition series metals of group $4$. They are found together in nature and are difficult to separate from each other.

Which of the following is the reason for the above?

The only Lanthanoid which is radioactive

Name a member of lanthanide series which is well known to exhibit $+4$ oxidation state

The electronic configuration of gadolinium (At. No. $64$) is

Which of the following oxidation states is the most common among the lanthanoids?

The third ionization enthalpy is expected to be very low for

Among the lanthanide $\mathrm{Eu}, \mathrm{Tb}, \mathrm{Er}$ and $\mathrm{Dy}$, which one readily forms stable divalent ions?

The position of inner transition elements is

Which of the following oxidation states is common for all lanthanoid?

Lanthanide contraction is caused due to:

The general oxidation state of Lanthanoids is _____.

The element with atomic number $61$ belongs to which group?

Which of the following statement is not correct :-

In $\mathrm{d}$-Block when atomic size of one series are compared with those of corresponding element in other series :-
(I) Increase from the first $\left(3\mathrm{d}\right)$ to second $\left(4\mathrm{d}\right)$ series
(II) Increase from the second $\left(4\mathrm{d}\right)$ to third $\left(5\mathrm{d}\right)$ series
(III) Virtually the same as first $\left(3\mathrm{d}\right)$ and in second $\left(4\mathrm{d}\right)$ series
(IV) Virtually the same as second $\left(4\mathrm{d}\right)$ and in third $\left(5\mathrm{d}\right)$ series

The most common oxidation state of lanthanoids is

The general oxidation state of Lanthanoid series is

Gadolinium $\left(\mathrm{Gd}\right)$ has $4{\mathrm{f}}^{7}5{\mathrm{d}}^{1}6{\mathrm{s}}^2$ electronic configuration outside the $\left[\mathrm{Xe}\right]$ core. Find spin magnetic moment of ${\mathrm{Gd}}^{3+}$