A balanced equation is an equation that has an equal number of atoms of elements on either side of the equation.
Chemical equations are balanced to obey the law of conservation of mass which states that the mass of reactants and that of the product should always be equal in chemical reactions.
Therefore, the balanced chemical equation for the reaction between Sr and F₂ is given by;
Sr(s) + F₂(g) → SrF₂(s)
Each side of the equation has 1 atom of Sr and two atoms of F thus the equation is balanced.
