Redox

• Electrons are transferred when reduction and oxidation occurs, represented by the acronym OIL RIG: Oxidation is the loss of electrons and reduction is the gain.
• Calcium completely burning an oxygen involves a reduction and an oxidation process, making it a redox reaction.
• Reducing agents lose electrons but are themselves oxidized.
• Each element can be assigned an oxidation number or oxidation state, which depends on a set of rules.
• Uncombined elements and combined elements always have an oxidation state of zero.
• Ions and oxidation numbers have the same value as the charge in the iron.
• Group ones are always +1 and group twos are always +2.
• Aluminium is always +3 and hydrogen is always -1.
• Sodium, when combined with chlorine, forms sodium chloride, indicating a reduction of sodium from zero to one oxidation number and an increase in chlorine from zero to minus one oxidation number.
• Calcium, when reacting with acids, goes from zero to plus two oxidation numbers.
• When metals react with acids, the metal is oxidized and hydrogen is reduced.
• Metals, when reacting with acids, are oxidized and a salt and hydrogen gas is formed.
• Chlorine has an oxidation state of +3.
• Clo2 has one chlorine atom bonded to two oxygens, each with a negative charge of -2, resulting in a total overall charge of -4.
• Vanadium 5 oxide is a compound with two oxygens, each with a negative charge of -2, resulting in a total overall charge of +5.
• Hydrogen in a compound, such as HF, has a negative oxidation state because it is bonded to a metal.
• Sodium has a +1 oxidation state because it is in group one.
• Chlorine is always -1.
• Fluorine always has an oxidation number of -1, regardless of what it's bonded to.
• In NH3, the nitrogen has an oxidation number of -3, because there are three hydrogen atoms bonded to it.
• In H2O2, oxygen is -1, because it's bonded with a hydride.
• Chlorine's oxidation number is +3, because it's bonded with furry, which is more electronegative than chlorine.
• Lithium dioxide has an oxidation number of -2, because oxygen has the value of -2 in hydrogen peroxide.
• In H2S, the sulfur has an oxidation number of -2, because there are two hydrogen atoms bonded to it.
• Oxygen is always zero when it's uncombined, because that's rule number one.
• In Fe2O3, oxygen is -2, because there are three iron ions bonded to it.
• In V2O5, oxygen is +4, because there are two vanadium ions bonded to it.
• Oxygen's oxidation number is usually -1, except in peroxides and superoxides, where it's +2.
• In H2SO4, oxygen is -2, because there are four sulfate ions bonded to it.