• Statement (D): The stability of the +5 oxidation state decreases down the group due to the inert pair effect.
• Statement (E): Nitrogen belongs to the second period and cannot expand its octet, hence it cannot show a maximum covalency of 6.
Corrected Statements: - +5 oxidation state stability decreases down the group. - Nitrogen shows a maximum covalency of 4.
Let \( S = \left\{ m \in \mathbb{Z} : A^m + A^m = 3I - A^{-6} \right\} \), where
\[ A = \begin{bmatrix} 2 & -1 \\ 1 & 0 \end{bmatrix} \]Then \( n(S) \) is equal to ______.