`=>` The oxidation number for an atom of any free (uncombined) element is ZERO. e.g `Na, Ca`
`=>` The oxidation number of an element in self-combination is always ZERO. e.g, `H_2 , O_2`
`=>` In most hydrogen containing compounds, oxidation number of hydrogen is +1. (Exception is when `H` combines with alkali metals or alkaline earth metals to form hydrides of metals such as : `NaH, LiH, CaH_2`. Then, the oxidation number of `H` is -1).
`=>` In compounds involving the alkali metals, the elements are assigned oxidation number of +1. In compounds involving the alkaline earth metals, the elements are assigned oxidation number of +2.
`=>` Oxygen is usually assigned an oxidation number of -2 for oxides. It has an oxidation number of -1 in peroxide (`H_2O_2`).
`=>` Oxidation number of oxygen in peroxides like `H_2O_2 , Na_2O_2` is `-1` in superoxides like `KO_2 , RbO_2` it is `-1/2` and and compounds in which O-atom bonded to fluorine like `OF_2 , O` is in +2 while in `O_2F_2` is in +1 state.
`=>` Fluorine always has oxidation number of -1 in compounds. The other elements in that group are usually -1 in compound with elements of low electronegativity.
`=>` The sum of oxidation numbers of all the atoms in the formula for a neutral compound is ZERO.
`=>` The sum of oxidation numbers of an ion or complex ion is the same as the charge on that ion.
`=>` Negative oxidation number in compounds of two unlike atoms is assigned to the more electronegative atom.
`=>` In combinations of non-metals not involving hydrogen and oxygen, the nonmetal that is more electronegative is considered negative.
`=>` The common oxidation state of alkali metal (e.g. Li, Na, K etc.) is +1.
`=>` The oxidation number of alkaline earth metals (e.g. Be, Mg, Ca, Ba, etc.) is +2.
`=>` Oxidation number of metal in metal carbonyl is zero. e.g. `Fe` is in 0 oxidation state in `Fe(CO)_5`.
`=>` In `C_3O_2` [carbon suboxide] oxidation number of carbon is `4/3, Br_3O_8`, [tribomooctaoxide ], `Br` is in `16/3` oxidation state and `Na_2S_4O_6` [sodium tetrathionate], `S` is in 2.5 oxidation state.
`=>` The oxidation number for an atom of any free (uncombined) element is ZERO. e.g `Na, Ca`
`=>` The oxidation number of an element in self-combination is always ZERO. e.g, `H_2 , O_2`
`=>` In most hydrogen containing compounds, oxidation number of hydrogen is +1. (Exception is when `H` combines with alkali metals or alkaline earth metals to form hydrides of metals such as : `NaH, LiH, CaH_2`. Then, the oxidation number of `H` is -1).
`=>` In compounds involving the alkali metals, the elements are assigned oxidation number of +1. In compounds involving the alkaline earth metals, the elements are assigned oxidation number of +2.
`=>` Oxygen is usually assigned an oxidation number of -2 for oxides. It has an oxidation number of -1 in peroxide (`H_2O_2`).
`=>` Oxidation number of oxygen in peroxides like `H_2O_2 , Na_2O_2` is `-1` in superoxides like `KO_2 , RbO_2` it is `-1/2` and and compounds in which O-atom bonded to fluorine like `OF_2 , O` is in +2 while in `O_2F_2` is in +1 state.
`=>` Fluorine always has oxidation number of -1 in compounds. The other elements in that group are usually -1 in compound with elements of low electronegativity.
`=>` The sum of oxidation numbers of all the atoms in the formula for a neutral compound is ZERO.
`=>` The sum of oxidation numbers of an ion or complex ion is the same as the charge on that ion.
`=>` Negative oxidation number in compounds of two unlike atoms is assigned to the more electronegative atom.
`=>` In combinations of non-metals not involving hydrogen and oxygen, the nonmetal that is more electronegative is considered negative.
`=>` The common oxidation state of alkali metal (e.g. Li, Na, K etc.) is +1.
`=>` The oxidation number of alkaline earth metals (e.g. Be, Mg, Ca, Ba, etc.) is +2.
`=>` Oxidation number of metal in metal carbonyl is zero. e.g. `Fe` is in 0 oxidation state in `Fe(CO)_5`.
`=>` In `C_3O_2` [carbon suboxide] oxidation number of carbon is `4/3, Br_3O_8`, [tribomooctaoxide ], `Br` is in `16/3` oxidation state and `Na_2S_4O_6` [sodium tetrathionate], `S` is in 2.5 oxidation state.