Sketch and label the silicon-oxygen tetrahedron. Describe the five principle silicate structures and give an example of each. Number of protons in the nucleus gives atomic number of element. Combined weight of the protons and neutrons gives atomic weight. Number and location of electrons controls chemical behavior.
Some atoms tend to gain electrons and become negatively charged anions .
Other atoms tend lose electrons, forming positively charged cations . The resulting charge on an atom is its valence. Strength of an ionic bond decreases as bond length increases. Ionic bonds predominate type in mineral structures. Chemical bonds in some minerals are intermediate between these two extremes.