The silicon atom's fourteen protons are balanced with an equal number of electrons. Oxygen and silicon ions with negative and positive charges respectively. The oxygen anion has gained two electrons whereas the silicon cation has lost four electrons. Ions of individual elements combine together to form mineral compounds by chemical bonding . Hydrogen and oxygen atoms share two electrons by covalent bonding to form water.
Covalent bonds are typically stronger than ionic bonds.
For example, quartz , formed by covalent bonding between silicon and oxygen, is one of the most resistant common minerals and diamond , the hardest mineral, is formed by covalent bonding between carbon atoms. Although at first they may appear to have nothing in common, a bowl of breakfast cereal and a pile of rocks share common elements. Rocks and breakfast cereal represent components of a geochemical cycle that begins when elements are naturally extracted from rocks as minerals break down at the earth's surface to form soil. The elements are absorbed by crops growing in the soils and may find their way to us in the foods we eat. Many of these are essential for human health.