What is the oxidation number for elements?

Answer 1

The oxidation number of O in any elemental form (e.g. O2, O3) is zero. Typically in chemical compounds the oxidation number of O is -2 (oxide ion)

Answer 2

The oxidation number of a central atom in a coordination compound is the charge that it would have if all the ligands were removed along with the electron pairs that were shared with the central atom.[1] It is used in the nomenclature of inorganic compounds. It is represented by a Roman numeral; the plus sign is omitted for positive oxidation numbers. The oxidation number is placed either as a right superscript to the element symbol, e.g. FeIII, or in parentheses after the name of the element, e.g. iron(III): in the latter case, there is no space between the element name and the oxidation number.

The oxidation number is usually numerically equal to the oxidation state. However, in a few cases the ligand atom can be less electronegative than the central atom (e.g., in iridium phosphine complexes), resulting in a formal oxidation state that is different from the oxidation number.

Answer 3

In chemistry, the oxidation state is an indicator of the degree of oxidation. Oxidation is a reduction of electrons. If Mn (zero oxidation state in elemental form) loses an electron it become Mn+ that is oxidation state 1. If it loses 3 electrons to become Mn3+ is is in oxidation state +3

Answer 4

The official definition of IUPAC is the following:
"Oxidation state of an atom is the charge of this atom after ionic approximation of its heteronuclear bonds,
(and the term oxidation number is nearly synonymous)".

Answer 5

Apex The charge an element would have if it were an ion