What is the number of elements present in each series of transition elements?

Among the following series of transition metal ions,the one in which all the metal ions have $3d^2$ electronic configuration (excluding the $3p^6$ core) is (Atomic number: $Ti=22, V=23, Cr=24, Mn=25$)

In the electronic configuration of which of the given elements,$Aufbau$ principle or $(n+l)$ rule is violated?

Write down the electronic configuration of:
$(i) Cr^{3+}$
$(ii) Pm^{3+}$
$(iii) Cu^{+}$
$(iv) Ce^{4+}$
$(v) Co^{2+}$
$(vi) Lu^{2+}$
$(vii) Mn^{2+}$
$(viii) Th^{4+}$

The correct option with the order of melting points of the pairs $(Mn, Fe)$, $(Tc, Ru)$ and $(Re, Os)$ is $:$

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