Question

state one chemical property which can be used to distinguish a metal from a non metal

Answer 1

While considered more a physical property than a chemical property, metals are electrically conductive due to an overlap of energy between the valance band and conduction band. This results in the electronic conduction band being partially filled.

Non-metals have a large energy band gap between the valance and conduction bands and therefore are non-conductive.

Metalloids are semiconductors and have small enough bandgaps where electrons can be excited from the valance band into the conduction band by either thermal energy or an electrical potential.