Though Sn and Si are 4^ th group elements, Sn is a metal while Si is a semiconductor because

Step-by-step solution

The electrical nature of a material depends on the energy gap between the valence band and the conduction band. In Sn (white tin), the valence and conduction bands overlap, giving an effective energy gap of zero. Electrons can move freely, making it a metal. In Si, there is a small but finite energy gap (~1.1 eV), allowing only limited electron excitation at room temperature, making it a semiconductor. Among the given options, the defining characteristic is that the energy gap of Sn is zero while that of Si is fini