What kind of chemical reaction does the chemical equation sodium plus chlorine --> sodium chloride represent?

Chemical reactions convert reactants to products, whose properties differ from those of the reactants. Chemical equations are a compact and convenient way to represent chemical reactions. They have the general form

Reactant(s) → Product(s)

The arrow in the equation means "changes to" or "forms." The reaction of gaseous nitrogen with hydrogen to produce ammonia, NH 3 , is represented by the chemical equation

Although there are thousands of chemical reactions, a significant number of them, especially those that are not organic reactions, can be classified according to four general patterns: combination, decomposition, displacement, and exchange.

"the periodic table is arranged in order of atomic number."