Most atomic nuclei in the universe are stable. This means the number of protons in a stable atom's nucleus remains constant indefinitely. Consequently, a stable atom retains its elemental identity regardless of any envir... More » Science Physics Particle Physics

Hydrogen and ununoctium are two examples of the more than 100 elements that have either been discovered in nature or synthesized by scientists. All of the elements are arranged in the periodic table, which organizes the ... More »

Gold is a chemical element. Its symbol on the periodic table is Au, and it is classified as a transition metal. It has an atomic number of 79, which is one of the higher atomic numbers of elements that occur naturally. More » Science Chemistry

Nuclear force is the force that holds the particles of atomic nuclei, protons and neutrons, together. It is a fundamental force able to overcome the electric force that would otherwise force the nucleus apart within extr... More »

String theory involves the view of the manifestation of all fundamental particles in the universe and the configuration of the fundamental strings. A string is regarded as a one-dimensional filament of energy and is thou... More »

String theory helps human beings understand the nature of the universe and how it works. There are no practical applications for string theory, as of 2014. More » Science Physics Particle Physics

The electron sea model explains how metallic elements bond to each other. The valence electrons of each element are delocalized and are free to move around the fixed proton centers as if they were floating in a sea of el... More »