Most of the metals react with oxygen to form metal oxides.
For example: magnesium reacts with oxygen to form magnesium oxide. The reaction involved is:
$\text{2Mg(s)}+{\text{O}}_2\text{(g)}\to \text{2MgO(s)}$
The metal oxide form alkali solution when dissolved in water. This solution turns red litmus paper to blue. Hence, these metal oxides are basic in nature.

Sodium is a metal ion which combines with an ion of the non-metal chlorine(Cl) to form sodium chloride also know as the common salt.

An amphoteric oxide is an oxide that can act both as an acid and as a base. An example is aluminum oxide, $A{l}_2$$O_3$. It reacts with acids to form the corresponding aluminum salt, and with bases to form salts called aluminates.

When one metal replaces another metal from its salt solution, the type of reaction is termed as a displacement reaction.

Non metals are bad conductors of heat and electricity and hence they are called as insulators.