Refer to the reaction between magnesium and oxygen In the introduction. What elements is oxidizing?write the oxidation number for the reactants and product to show the oxidation

Oxidizing element: Mg

Explanation:

Reaction of magnesium and oxygen can be written as:

while writting chemical reaction between two atom or element then write their natural form i.e. how that atom or element exist in the nature.

eg. reaction of any element with Oxygen atom then we can not write directly O because oxygen exist in the nature in form of

finding oxidation number each side:

Reactant side:

Mg=0;

O=0;

product side:

Mg=+2;

O=-2;

from above:

oxidation number of Mg is increasing hence this is oxidizing element

the answer is barium and copper bromide