Dear student,
A skeletal equation is such a chemical reaction in which, the reactant and products are identified with their chemical formula but their quantity and proportion is not identified . For ex:
Formation of magnesium oxide by burning Mg -ribbon in presence if oxygen as:
Mg + O2 -> MgO
The above equation is just a skeletal equation where the formulas are written but the no. of atoms are not balanced so the balanced chemical equation is ,
2Mg + O2 -> 2MgO
Regards