[AntonioLao]

Putting all other chemical properties aside, the unique atomic radius and the ionic radius of elements in the periodic table can be used as proofs for the existence of a theorem on a principle of proximity.

Generally, this principle asserts that the interactions of matter with matter, energy with energy, vacuum with vacuum, matter with energy, matter with vacuum, and energy with vacuum follow along a logical understanding of how close or how near they are to each other. This can help to clarify the physical concept of temperature and many other intensive physical variables, e.g., pressure, density, and viscosity. Most people agree that a macroscopic system can well be described by a single extensive variable. However, the same system must well be described by a set of intensive variables. Some examples of extensive variables are volume, mass, and total energy. On the other hand, if an extensive variable is divided by an arbitrary extensive one, the final outcome is an intensive variable and no more division is possible, exemplifying the quantum nature of its origin.

The atoms of life are well known as hydrogen, carbon, oxygen, and nitrogen with rare appearance of phosphorus and sulfur. Coincidently, when their atomic radii are normalized to unity relative to oxygen, carbon, and nitrogen, hydrogen gives ½ while phosphorus and sulfur both give 4/3. The others could not be normalized within the integral value of 4. However, their ionic radii become 1/5 for carbon, 2 for both oxygen and nitrogen, 8/3 for both phosphorus and sulfur. These relative radii proximity seems to what gave life possible.