A Chemical symbol represents a specific element or an atom of an element. A chemical symbol makes it easier to write a chemical reaction. A Valence describes how easily an atom or radical can combine with other chemical species. The Language of Chemistry or Chemical Equations, published in 2010, is a book that covers different types of chemical equations. Chemistry is a branch of science that deals with the interaction of atoms and other types of energy. SELINA Solutions helps you to attain a basic knowledge of Chemistry such as symbols, valence, radicals, compounds, chemical equations, atomic weights, molecular weight and calculation of relative molecular mass and percentage composition of a compound.