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Elementary particles are particles with no measurable internal structure; that is, it is unknown whether they are composed of other particles. [1] They are the fundamental objects of quantum field theory. Many families and sub-families of elementary particles exist. Elementary particles are classified according to their spin.
In particle physics, an elementary particle or fundamental particle is a subatomic particle that is not composed of other particles. [1] The Standard Model presently recognizes seventeen distinct particles—twelve fermions and five bosons.
Quantities, Units and Symbols in Physical Chemistry, also known as the Green Book, is a compilation of terms and symbols widely used in the field of physical chemistry. It also includes a table of physical constants , tables listing the properties of elementary particles , chemical elements , and nuclides , and information about conversion ...
Alpha particles, also called alpha rays or alpha radiation, consist of two protons and two neutrons bound together into a particle identical to a helium-4 nucleus. [5] They are generally produced in the process of alpha decay but may also be produced in different ways. Alpha particles are named after the first letter in the Greek alphabet, α.
The subatomic particles considered important in the understanding of chemistry are the electron, the proton, and the neutron. Nuclear physics deals with how protons and neutrons arrange themselves in nuclei. The study of subatomic particles, atoms and molecules, and their structure and interactions, requires quantum mechanics.
To differentiate between antiparticles and particles, a plus or negative sign is added in superscript. For example, the electron and the positron are denoted e − and e +. [26] However, in the case that the particle has a charge of 0 (equal to that of the antiparticle), the antiparticle is denoted with a line above the symbol.
The most common symbols for a wave function are the Greek letters ψ and Ψ (lower-case and capital psi, respectively). Wave functions are complex-valued . For example, a wave function might assign a complex number to each point in a region of space.
The list given in ISO 31-8:1992 was quoted from the 1998 IUPAC "Green Book" Quantities, Units and Symbols in Physical Chemistry and adds in some cases in parentheses the Latin name for information, where the standard symbol has no relation to the English name of the element. Since the 1992 edition of the standard was published, some elements ...