Some Applications Of D And F Block Elements

Chromium in the state has an electronic configuration of , which is relatively unstable and easily oxidizes to the more stable configuration, . This makes a strong reducing agent because it readily loses electrons. On the other hand, has an electronic configuration of , which is also unstable. It is prone to gaining electrons to become , which has a more stable configuration. Thus, is a strong oxidizing agent because it readily accepts electrons.

Thus, the differences in the electronic configurations of and explain why is a strong reducing agent and is a strong oxidizing agent.

The element of the 3d series with the lowest enthalpy of atomisation is copper (Cu). Copper has a completely filled configuration, which makes it highly stable. The stability of the configuration reduces the energy required to break the metallic bonds during atomisation, hence lowering the enthalpy of atomisation. In contrast, elements like zinc (Zn) and manganese (Mn) have less stable electron configurations and require more energy to break the bonds during atomisation.

Thus, copper (Cu) has the lowest enthalpy of atomisation due to the stability provided by its filled configuration.

Lanthanide contraction refers to the gradual decrease in the ionic radius of the lanthanide series as the atomic number increases, caused by the poor shielding effect of the 4f-electrons. Two important consequences of lanthanide contraction are: 1. Decreasing ionic radii: As the atomic number increases from to , the size of the ions decreases, leading to an increase in the effective nuclear charge experienced by the electrons. This results in a decrease in the ionic radii. 2. Similarity between the 3d and 4d/5d elements: The lanthanide contraction leads to similarities in the properties of the lanthanide elements and the d-block elements in the same period. For example, (a 4d element) and (a 5d element) have very similar ionic radii due to the lanthanide contraction.

Thus, the lanthanide contraction results in smaller ionic radii and increased similarities between the properties of lanthanides and d-block elements.