126 Some basic concepts about the chemistry of water - explained in very simple terms - and is intended for curious minds who wish to better understand the science behind water ionization at the molecular level. The structure of atoms and molecules. An atom consists of positively charged protons, electrically neutral neutrons and negatively charged electrons. At the centre of the atom, neutrons and protons stay together to form the atom's core or nucleus. Electrons revolve around the atom's core in three-dimensional orbits or shells. Each of these molecular orbits needs a certain number of electrons to be stable. The inner orbit closest to the core must contain 2 electrons to be stable. The second orbit must contain 8 electrons to be stable. Each subsequent orbit, for atoms that contain more than 10 protons and electrons, also requires a pre-defined number of electrons to be stable. But apart from inert gases such as helium, neon and argon, the outermost orbit of most atoms is missing one or more electrons to be stable. In order to reach a state of stability, atoms bond together to form molecules by sharing their valence electrons, or electrons that make up the outermost shell.
sharing can be achieved through covalent bonding as described below. Covalent bonding of a water molecule Covalent bonding is a form of chemical bonding between two non-metallic atoms, such as hydrogen and oxygen, which is characterized by the sharing of pairs of electrons between two or more atoms. For stabilization, they share their valence electrons with other atoms. A water molecule is an example of a molecule created through covalent bonding. Water is made up of one oxygen atom and 2 hydrogen atoms, hence the chemical symbol H2O. A hydrogen atom is made up of 1 proton at its core and 1 electron that revolves around the core in a three-dimensional orbit. An oxygen atom is made up of 8 protons and 8 neutrons at its core and 8 electrons that revolve around the core in 2 separate three-dimensional orbits. The inner orbit contains 2 electrons whereas the outer orbit contains 6 electrons. However, both the hydrogen atom and the oxygen atom are not stable when they are alone. In order to be stable, the hydrogen atom must contain 2 electrons in its shell, and the oxygen atom must contain 8 electrons in its outer shell.