Question

How does metal and non-metal react?

Answer 1

Hint: Metals are identified by the property that they have free valence electrons which can be easily removed or donated while the non-metal are identified by the property that they require some electrons to complete their octet so, they gain or attract electrons towards themselves.

Complete answer:
We knew that the elements are arranged in a systematic order in the periodic table so, on the left side of the periodic table we get metals like sodium ($Na$), magnesium ($Mg$), potassium ($K$), etc and on the right side of the periodic table we get non-metals like oxygen ($O$), chlorine ($Cl$), sulfur ($S$), etc.
Metals are identified by the property that they have free valence electrons which can be easily removed or donated because the metals are highly electropositive elements while the non-metal are identified by the property that they require some electrons to complete their octet so, they gain or attract electrons towards itself because they are highly electronegative elements.
So, when the metals donate electrons and these electrons are attracted by the non-metals then there is the formation of a bond and this bond is an ionic bond.
For example, sodium, which is a metal, can donate one electron, and chlorine, which is a non-metal, gains the electron from the sodium and forms an ionic bond which results in the formation of sodium chloride ($NaCl$).

Note:
If the reaction takes place between non-metal and nonmetal, then there is sharing of electrons from each element leading to the formation of a covalent bond.