What is Oxidation state?
[[File:Plutonium in solution.jpg|thumb|Some elements like [[plutonium]] have multiple oxidation states. We tell them apart by writing the oxidation number with a [[roman numeral]].]] [[File:The-Periodic-Table-Of-Oxidation-States-2016.webp|thumb|Periodic table with oxidation states]] The '''oxidation state''' (or '''oxidation number''') of an [[chemical element|element]] is used to predict what sort of [[chemical compounds]] form. Every [[chemical element|element]] has oxidation states that it likes, and will not form compounds that would put it in a bad state. You can look up the oxidation state(s) of an element on many [[periodic table]]s. They are usually between −2 and +3. A pure element always has an oxidation state of 0. == History == Oxidation states were invented by [[Antoine Lavoisier]] to predict how oxygen reacted in [[chemical reaction]]s; hence the name. Later on, we learned that Lavoisier's theory can be used to predict other reactions too, many of them have nothing to do with oxygen. == Examples == [[Oxygen]] wants the -2 state, while [[hydrogen]] likes +1. Two hydrogen atoms stick to one oxygen atom to give a [[water]] molecule, {{chem2|H2O}}. Oxygen can't have the -3 state, so they can't form {{chem2|H3O}}. [[Uranium]] has two important oxidation states, +4 and +6. [[Fluorine]] always has the -1 oxidation state in compounds. To make [[nuclear fuel]], uranium tetrafluoride {{chem2|UF4}}, which has uranium in the +4 state and four fluorine atoms in the -1 state, is treated with elemental fluorine (two fluorine atoms in the 0 state): :{{chem2|UF4 + F2 -> UF6}} The uranium atom changes from the +4 to the +6 state, and the two fluorine atoms change from the 0 state to the -1 state. [[Carbon]] can form compounds with oxidation states anywhere from -4 to 4. The carbon atom has the -4 state in [[methane]], the -2 state in [[methanol]], the 0 state in [[formaldehyde]], the +2 state in [[formic acid]], and the +4 state in [[carbon dioxide]]. Odd states can be seen in compounds with two carbons: both