The transition metal with the highest melting point is:

In transition elements,the orbitals that are partially filled by electrons are:

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

Assertion : Transition metals show variable valency.
Reason : Transition metals have a large energy difference between the $ns^2$ and $(n-1)d$ electrons.

Which of the following statements is correct?

What is the value of the spin-only magnetic moment of $Ni$ $(Z=28)$ in the $+2$ oxidation state (in $BM$)?