Question

Match the properties given in Column I with the metals given in Column II.

	Column I (Property)		Column II (Metal)
(A)	An element which can show +8 oxidation state	(i)	Mn
(B)	3d block element that can show upto +7 oxidation state	(ii)	Cr
(C)	3d block element with highest melting point	(iii)	Os
		(iv)	Fe

Answer 1

Part (A)

The electronic configuration of Osmium (Os) is$\left[Xe\right]4f^{14}5d^{6}6s^2$ . Thus, it can lose 8 electrons to attain stable configuration and hence it can exist in +8 oxidation state. For example, in compounds like $Os{O}_4$, $\left(A\right)\to \left(iii\right)$.

Part (B)

The electronic configuration of Manganese (𝑀𝑛) is $\left[Ar\right]3d^{5}4s^2$. Thus, it can lose 7 electrons to attain stable noble gas configuration and hence it can exist in +7 oxidation state. For example, in compounds like $M{n}_2{O}_7,KMn{O}_4$,$\left(B\right)\to \left(i\right)$

Part (C)

A metal has a high melting point because of a higher number of metal-metal bonds and the number of metal-metal bonds increases with increase in unpaired electrons. In the 3d transition series, chromium (𝐶𝑟) has the highest number of unpaired electrons, thus has the highest melting point. $\left(C\right)\to \left(ii\right)$

$\left(A\right)\to \left(iii\right),\left(B\right)\to \left(i\right),\left(C\right)\to \left(ii\right)$