Question

On what basis can we say that Cu is a transition element but Zn is not? (Atomic number: Cu = 29, Zn = 30)

Answer 1

Cu is a transition element because it has an incomplete d-orbital in its +2 oxidation state, whereas Zn has a fully filled d-orbital in its ground state as well as in +2 oxidation state, making it a non-transition element. Transition elements must have at least one oxidation state with an incomplete d-orbital.

Answer 2

Transition elements show a variety of oxidation states because both (n-1)d and ns subshell electrons take part in bond formation due to their comparable energies. This allows for the formation of multiple oxidation states. The presence of unpaired electrons in d-orbitals also contributes to this variability.

Answer 3

The irregular trends in $\text{E\(^0\)}_{M^{2+}/M }$ values from Vanadium to Zinc are due to irregular values of \((\Delta H(_1) + \Delta H(_2))\) and sublimation enthalpies. These values are influenced by factors like the ionization energies and the differences in the stability of the ions formed.

Answer 4

In transition metals, oxidation states vary by +1, whereas in non-transition metals, oxidation states differ by +2. This is due to the involvement of d-orbitals in transition metals, which allows for a greater variety of oxidation states.

Answer 5

Cr\(^{2+}\) is strongly reducing because it will be converted to Cr\(^{3+}\), which has a more stable half-filled t\(_2\)g configuration. On the other hand, Mn\(^{3+}\) is strongly oxidizing because it changes to Mn\(^{2+}\), which has a more stable half-filled d\(^5\) configuration. The stability of these configurations makes Cr\(^{2+}\) more likely to donate electrons, and Mn\(^{3+}\) more likely to accept electrons.

Answer 6

The ionic equation is: \[ 2MnO_4^- + H_2O + I^- \rightarrow 2MnO_2 + 2OH^- + IO_3^- \]