The element with atomic number $23$ is placed in the periodic table in:

For the transition elements $Cr, Mn, Fe,$ and $Co$,the correct order of the negative values of $E^o_{M^{2+}/M}$ is:

Assertion $(A)$: Transition elements have higher enthalpies of atomization.
Reason $(R)$: Large number of unpaired electrons present in transition elements facilitate strong interatomic interaction and strong bonding between atoms.

Which element from the following exhibits a common oxidation state of $+2$ only?

Which of the following is ferromagnetic in nature?

The correct decreasing order of spin only magnetic moment values $(BM)$ of $Cu^{+}$,$Cu^{2+}$,$Cr^{2+}$ and $Cr^{3+}$ ions is $:$