Identify the major product (G) in the following reaction (Bromination with \( Br_2/FeBr_3 \)).
Conc. HNO\(_3\)
\( \text{M} \xrightarrow{\text{CH}_3\text{MgBr}} \text{N} + \text{CH}_4 \uparrow \xrightarrow{\text{H}^+} \text{CH}_3\text{COCH}_2\text{COCH}_3 \)
Identify the ion having 4f\(^6\) electronic configuration.