Question

Which $3d$-series transition element has the highest melting point?
A) $Fe$
B) $Cr$
C) $Mn$
D) $Ni$

Answer 1

Transition elements (otherwise called transition metals) are components that have incompletely filled d orbitals. IUPAC characterizes transition components as a component having a d subshell that is halfway loaded up with electrons, or a component that can shape stable cations with a not entirely filled d orbital. Commonly, any component which relates to the d-block of the modern periodic table (which comprises groups 3-12) is viewed as a transition element. Indeed, even the f-block components including the lanthanides and the actinides can be considered as transition metals.

Complete answer:
The d-block components with more number of unpaired electrons will have a high melting point as the more number of unpaired electrons present, the stronger will be the metallic bond formation. Henceforth the necessity of heat to release the bond will be high.

_{26}Fe:[Ar]4{s^2}3{d^6} \\\ _{24}Cr:[Ar]4{s^1}3{d^5} \\\ _{25}Mn:[Ar]4{s^2}3{d^5} \\\ _{28}Ni:[Ar]4{s^2}3{d^8} \\\ \end{gathered} $$ So, as we can see that $$Cr$$contains the maximum number of unpaired electrons hence has the highest melting point. **Hence,the correct option is B.** **Note:** The transition metals display ordinary metallic properties, for example, pliability, malleability, high elasticity, and metallic shine. They are commonly great conduits of warmth and power and will in general solidify in BCC (body-focused cubic), CCP (cubic close-stuffed), or HCP (hexagonally close-pressed) structures. However, patterns can be seen in the metallic properties of the change components. For instance, components such as chromium and molybdenum are some of the hardest transition metals because they contain many unpaired electrons.