Metals have one to three electrons in their outer shell, whereas non-metals have four to eight electrons. Another difference is that metals tend to lose their valence electrons, but non-metals share or gain valence electrons. Where metals form oxides which are basic, non-metals form oxides which are acidic.While metals are very good reducing agents, non-metals are very good oxidising agents. Now, considering the difference between their physical properties, metals are malleable, which means it can be beaten to thin sheets.On the other hand, non-metals are very brittle. When comparing their density, metals have a high to moderate density, whereas non-metals have low to moderate density.etals and non-metals can be easily differentiated. In the periodic table, the metals are placed on the left, and the non-metals on the right. First of all, let’s look at the difference in the chemical properties between metals and non-metals.