Question

Examine the reactants of the incomplete synthesis reaction. 2Mg + O2 → __________.
Which of the answer choices correctly predicts the product of the synthesis reaction?
O2 + 2Mg
Mg + Mg + O2
2MgO
O2Mg

Answer 1

2MgO
This is called redox reaction. Oxygen is the oxidizing agent to receive 2 electrons from Mg.
Mg is the reducing agent to give 2 electrons to O.
Mg becomes Mg2+ and O becomes O2-. These 2 ions form an ionic structure called MgO

Answer 2

Answer: $2MgO$

Explanation:

Synthesis reaction is a chemical reaction in which two reactants are combining to form one product.

According to the law of conservation of mass, mass can neither be created nor be destroyed. Thus the mass of products has to be equal to the mass of reactants. The number of atoms of each element has to be same on reactant and product side. Thus chemical equations are balanced.

$2Mg+O_2\rightarrow 2MgO$

Thus the products of chemical reaction will be $2MgO$