2naoh+h2so4 na2so4+h2o the equation is balanced/unbalanced because the number of hydrogen atoms and oxygen/sodium is equal/not equal in the reactants and in the products

Your equation is:


An equation is balanced only if there are the same number of atoms of each element on both sides of the arrow - aka same number of atoms of each element in both reactants (left of the arrow) and products (right of the arrow). 

It'll be easiest to tackle this by counting up the number of atoms of each element on the left and on the right and comparing those numbers. If there is a number in front of the entire compound, that means that number applies to all elements in the compound. If the number is a subscript (little number to the right of the element), that means that number only applies to the element that the subscript is attached to:
1) On the left, you have:


2) On the right, you have:


You can see that the number of oxygen and hydrogen atoms aren't equal on both the left (reactants) and the right (products), so the equation is unbalanced.

Your final answer is "The equation is unbalanced because the number of hydrogen atoms and oxygen is not equal in the reactants and in the products."