Among the following metals,the most dense 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 of the following transition metals is considered the softest?

Identify the order in which the spin-only magnetic moment (in $BM$) increases for the following four ions:
$(I) Fe^{2+}$
$(II) Ti^{2+}$
$(III) Cu^{2+}$
$(IV) V^{2+}$

Which of the following metals exhibits more than one oxidation state?

Which of the following ions will exhibit colour in aqueous solution?