Avogadro constant Avogadro constant In chemistry and physics, the Avogadro constant, named after scientist Amedeo Avogadro, is the number of constituent particles, usually atoms or molecules, that are contained in the amount of substance given by one mole. Thus, it is the proportionality factor that relates the molar mass of a substance to the mass of a sample. The Avogadro constant, often designated with the symbol "N" or "L", has the value in the International System of Units (SI). (The parentheses there represent the degree of uncertainty.) Previous definitions of chemical quantity involved the Avogadro number, a historical term closely related to
Rutherford (unit) unit for activity, the rutherford became obsolete, and it is no longer commonly used. The following table shows radiation quantities in SI and non-SI units: Rutherford (unit) The rutherford (symbol Rd) is a non-SI unit of radioactive decay. It is defined as the activity of a quantity of radioactive material in which one million nuclei decay per second. It is therefore equivalent to one megabecquerel, and one becquerel equals one microrutherford. One rutherford is equivalent to 2.703 × 10 curie. The unit was introduced in 1946. It was named after British/New Zealand physicist and Nobel laureate Lord Ernest Rutherford (Nobel