A skeleton equation is just a way of using the formulas to indicate the chemicals that were involved in the chemical reaction. "Mg + O2 MgO." This skeleton equationshows that magnesium reacts with oxygen to form magnesium oxide. Skeleton equation are used when you do not have to balence the equation.
a skeleton equation just shows the reaction, a balanced equation shows how many molecules of each reactant are needed and how many molecules of the products are formed
a "skeleton" equation shows the physical position of the atoms of a molecule with respect for each other along with their bonding, while a chemical equation just shows the number of each atom.
e.g. -
chemical - H2O
skeleton - H-O-H
balanced chemical equation shows that the products and the reactants are solid, liquid, gas or aqueous
balanced equation shows how many molecules of each reactant are needed and how many molecules of the products are formed
where as the skeletal chemical equation does not show this all things