Yes.
No: An oxidation number, if shown at all in a chemical formula, is shown with a superscript. The oxidation number is usually shown only for monatomic ions.
... as positive or negative numbers
To write chemical formulas with oxidation numbers, first determine the oxidation number of each element in the compound based on their typical values. Then, use these oxidation numbers to balance the charges of cations and anions in the compound. Finally, write the chemical formula using subscripts to ensure that the overall charge of the compound is neutral.
They are written in roman numerals
subscripts
This is the formula for Copper (II) Oxide Copper has two possible oxidation numbers (+2 or +1) since there are no written subscripts for in the formula CuO, copper's oxidation number must have been +2 (If it had been +1, the formula would be Cu2O and the name of the compound woould be Copper (I) Oxide)
Subscripts represent the number of atoms of an element in a molecule. They are written as small numbers to the right of the element symbol in a chemical formula. They indicate the ratio of elements in a compound.
Chemical formulas are written with the chemical symbol of each element followed by a subscript. If no subscript is written, it is understood to be 1. In a molecular formula, the subscripts indicate the number of atoms of each element that are present in one molecule. In a chemical formula for an ionic compound, the subscripts represent the lowest whole number ratio of ions in the compound.
Oxidation numbers help determine the correct ratio of elements in a compound. By assigning oxidation numbers to each element, it is possible to balance the charges to show a neutral compound. The sum of the oxidation numbers in a compound should equal zero for a neutral compound or the overall charge for an ion.
subscripts
subscripts
subscripts