a system in chemical nomenclature and notation of indicating the oxidation state of the significant element in a compound or ion by means of a Roman numeral that is used in parentheses after the name or part of the name designating this element and ending invariably in -ate in the case of an anion and that is placed. Stock nomenclature for inorganic compounds is a widely used system of chemical nomenclature developed by the German chemist Alfred Stock and first published in 1919. In the "Stock system", the oxidation states of some or all of the elements in a compound are indicated in parentheses by Roman numerals.
(2) subtracting the atomic number from the atomic mass number, because the mass number is the total number of protons and neutrons in an atom and the atomic number is the number of protons in an atom.