Which one of the following bonds produces a solid that reflects light in the visible region and whose electrical conductivity decreases with temperature and has high melting point ?

Step-by-step solution

Metallic bonding is formed due to attraction of valence (free) electrons with the positive ion cores. Their conductivity decreases with rise of temperature. When visible light falls on a metallic crystal, the electrons of atom absorb visible light, so they are opaque to visible light. However, some orbital electrons absorb energy and reach to excited state. They then return to their normal state, remitting light of same frequency.