Question

Balance the given equation.
$Na+{{O}_{2}}\to N{{a}_{2}}O$

Answer 1

Hint: A balanced chemical equation tells us the exact number of atoms on the reactants side and that of the products side. The combination reaction consists of a reaction between two species to form one product. The given reaction is of sodium with oxygen and is a combination reaction. The balancing will require writing the same number of moles of reactants and products by hit and trial.

Complete answer:
A chemical reaction is the process where there is some change in chemical composition of the reacting species. A chemical reaction can be expressed in the form of a balanced chemical equation. A balanced chemical equation consists of the same amount of reactants and the products. This consists of the same number of moles on the reactant and the product side.
A chemical equation is balanced by balancing the charges on the atoms that form a molecule; the charges should be the same at the reactant side as well as on the products side. We have been given a combination reaction between sodium and oxygen that forms sodium oxide, the reaction is:
$Na+{{O}_{2}}\to N{{a}_{2}}O$
This will be balanced through a hit and trial method. We will first look at the charges on the reactants and the products side, and then balance the charges by adding a number of moles.
Na has a charge of +1 while oxygen atom has -2 charge. So on the reactants side there is 1 sodium atom and two oxygen atoms, charge of Na is +1 and that of ${{O}_{2}}$is -4, so we will write 4 in front of Na so the charge will be +4.
$4Na+{{O}_{2}}\to N{{a}_{2}}O$
Now the products side has 2 Na and 1 O, while reactant has 4 Na and 2 O, so the product will have 2 moles that will balance both the sides as,
$4Na+{{O}_{2}}\to 2N{{a}_{2}}O$
Hence, the equation is balanced.

Note:
Sodium has a +1 charge because it has 1 electron in its outer shell that can be donated. While oxygen has -2 because it has 4 electrons in the 2p orbital that needs only 2 to complete its octet. The charge on the atoms is also called their oxidation state that tells the ability to lose or gain electrons.