Which is evidence that the reaction below is a redox reaction?
2na + cl2 _ 2nacl

the sodium atom is a pure element as a reactant and becomes part of a compound.
two different elements take part in the reaction.
oxidation occurs to both elements in the reaction.
there are no ions in the equation.

The correct answer is:

Two different elements take part in the reaction.

Explanation:

A redox reaction is generally defined as chemical reaction in which oxidation and reduction takes place simultaneously.It is a reaction between two species among which gain and loss of electrons takes place.

So, in the given reaction, sodium metal looses an electron to chlorine atom to form sodium chloride molecule.

Oxidation

Reduction