Distinguish between metals and non-metals with respect to the nature of their oxide.

(a) Nature of oxide: Oxides of metals are usually basic. Soluble basic oxides dissolve in water, forming an alkaline solution, whereas oxides of non-metals are usually acidic. Soluble acidic oxides dissolve in water, forming an acidic solution.
(b) Metals react with oxygen and form metallic oxides, which are basic in nature.
Metal $+$ Oxygen $\to$ metal oxide
Metal oxide $+$ water base $\to$ metal hydroxide
Example - Magnesium is metal, and when it reacts with oxygen, it forms magnesium oxide. When we dissolve magnesium oxide in water, it gives magnesium hydroxide. The reactions are given below.

$\Rightarrow 2Mg+O_2\to 2MgO$

$\Rightarrow MgO+H_{2}O\to Mg(OH{)}_2$

Nonmetals react with oxygen and form nonmetallic oxides, which are acidic in nature.
Nonmetal $+$ Oxygen $\to$ Nonmetal oxide
Non-metal oxide $+$ water $\to$ Acid
Example - Sulphur is a nonmetal, and when it reacts with oxygen, it forms sulphur dioxide. When we dissolve sulphur dioxide in water, it gives sulphurous acid. Reactions are given below.

$\Rightarrow S+O_2\to S{O}_2$

$\Rightarrow S{O}_2+H_{2}O\to H_{2}S{O}_3$