In school and college, we learnt that chemical elements combine with each other to form new substances, compounds, in very well-defined ways, obeying certain scientific rules. For example, we learned that two atoms of hydrogen and one atom of oxygen combine to form a molecule of water, and that one atom of sulfur combines with four atoms of oxygen to form a sulphate radical with electrical charge -2. In chemistry these rules of combination were explained in terms of valence and bonds, and in physics the rules were explained in terms of rings of electrons and the numbers of electrons in the outermost shells of the elements.
Word Ways: Vol. 37
, Article 4.
Available at: http://digitalcommons.butler.edu/wordways/vol37/iss4/4