With reference to transition metals which of the following statements are correct?

A. Electronic configuration is represented by \((n - 2)d^{1-10}ns^{1-2}\)

B. They exhibit catalytic property

C. Some of them form interstitial compounds

D. In \(Ni(CO)_4\) and \(Fe(CO)_5\), the oxidation state of \(Ni\) and \(Fe\) are \(+4\) and \(+5\) respectively.

Choose the correct answer from the options given below:

B, C only

The correct answer is option 4. B, C only.

Let us go through each of the given statements in detail:

A. Electronic configuration is represented by \((n - 2)d^{1-10}ns^{1-2}\): This statement is incorrect. The correct representation for the electronic configuration of transition metals is \((n-1)d^{1-10}ns^{0-2}\), where \(n\) is the principal quantum number. The \(d\) orbitals are typically one shell lower than the principal quantum number.

B. They exhibit catalytic property:  This statement is correct. Transition metals and their compounds often act as catalysts in various chemical reactions. They can undergo changes in oxidation states, providing multiple reaction pathways and facilitating the conversion of reactants to products.

C. Some of them form interstitial compounds: This statement is correct. Transition metals, due to their relatively small atomic sizes, can form compounds in which smaller atoms or molecules occupy the interstitial spaces in their crystal lattices. These interstitial compounds often exhibit unique properties.

D. In \(Ni(CO)_4\) and \(Fe(CO)_5\), the oxidation state of \(Ni\) and \(Fe\) are \(+4\) and \(+5\) respectively: This statement is incorrect. In these compounds, the metal is assigned a formal oxidation state based on the number of electrons it appears to have donated or accepted. In \(Ni(CO)_4\), the oxidation state of \(Ni\) is 0, and in \(Fe(CO)_5\), the oxidation state of \(Fe\) is \(–1\).

In summary:
Statement A is incorrect.
Statements B and C are correct.
Statement D is incorrect.

Therefore, the correct answer is 4. B, C only.