What is oxidation state

\( \newcommand\) • • • • This page discusses the various definitions of oxidation and reduction (redox ) in terms of the transfer of oxygen, hydrogen, and electrons. It also explains the terms oxidizing agent and reducing agent. Oxidation and Reduction with respect to Oxygen Transfer • Oxidation is the gain of oxygen. • Reduction is the loss of oxygen. For example, in the extraction of iron from its ore: Because both reduction and oxidation are occurring simultaneously, this is known as a redox reaction. An oxidizing agent is substance which oxidizes something else. In the above example, the iron(III) oxide is the oxidizing agent. A reducing agent reduces something else. In the equation, the carbon monoxide is the reducing agent. • Oxidizing agents give oxygen to another substance. • Reducing agents remove oxygen from another substance. Oxidation and Reduction with respect to Hydrogen Transfer • Oxidation is the loss of hydrogen. • Reduction is the gain of hydrogen. Notice that these are exactly the opposite of the oxygen definitions (#1). For example, ethanol can be oxidized to ethanal: An oxidizing agent is required to remove the hydrogen from the ethanol. A commonly used oxidizing agent is potassium dichromate(VI) solution acidified with dilute sulfuric acid. Ethanal can also be reduced back to ethanol by adding hydrogen. A possible reducing agent is sodium tetrahydridoborate, NaBH 4. Again the equation is too complicated to consider at this point. More precise definiti...

Oxidation-Reduction Reactions The term oxidation was originally used to describe reactions in which an element combines with oxygen. Example: The reaction between magnesium metal and oxygen to form magnesium oxide involves the oxidation of magnesium. The term reduction comes from the Latin stem meaning "to lead back." Anything that that leads back to magnesium metal therefore involves reduction. The reaction between magnesium oxide and carbon at 2000C to form magnesium metal and carbon monoxide is an example of the reduction of magnesium oxide to magnesium metal. After electrons were discovered, chemists became convinced that oxidation-reduction reactions involved the transfer of electrons from one atom to another. From this perspective, the reaction between magnesium and oxygen is written as follows. 2 Mg + O 2 2 [Mg 2+][O 2-] In the course of this reaction, each magnesium atom loses two electrons to form an Mg 2+ ion. Mg Mg 2+ + 2 e - And, each O 2 molecule gains four electrons to form a pair of O 2- ions. O 2 + 4 e - 2 O 2- Practice Problem 1: Determine which element is oxidized and which is reduced when lithium reacts with nitrogen to form lithium nitride. 6 Li( s) + N 2( g) 2 Li 3N( s) Click here to check your answer to Practice Problem 1 The Role of Oxidation Numbers in Oxidation-Reduction Reactions Chemists eventually extended the idea of oxidation and reduction to reactions that do not formally involve the transfer of electrons. Consider the following reaction. CO(...

[ "article:topic", "paramagnetic", "diamagnetic", "electronic configuration", "oxidation numbers", "transition metal", "electron configuration", "oxidation state", "ions", "showtoc:no", "atomic orbitals", "physical properties", "oxidation states", "noble gas configuration", "configuration", "energy diagrams", "Transition Metal Ions", "Transition Metal Ion", "delocalized", "license:ccbyncsa", "licenseversion:40" ] https://chem.libretexts.org/@app/auth/3/login?returnto=https%3A%2F%2Fchem.libretexts.org%2FBookshelves%2FInorganic_Chemistry%2FSupplemental_Modules_and_Websites_(Inorganic_Chemistry)%2FDescriptive_Chemistry%2FElements_Organized_by_Block%2F3_d-Block_Elements%2F1b_Properties_of_Transition_Metals%2FOxidation_States_of_Transition_Metals Expand/collapse global hierarchy • Home • Bookshelves • Inorganic Chemistry • Supplemental Modules and Websites (Inorganic Chemistry) • Descriptive Chemistry • Elements Organized by Block • d-Block Elements • Properties of Transition Metals • Oxidation States of Transition Metals Expand/collapse global location \( \newcommand\) • • • • • • • • • • The oxidation state of an element is related to the number of electrons that an atom loses, gains, or appears to use when joining with another atom in compounds. It also determines the ability of an atom to oxidize (to lose electrons) or to reduce (to gain electrons) other atoms or species. Almost all of the Introduction Filling atomic orbitals requires a set number of electrons. The s-block ...

When I took high school chemistry many years ago, considerable effort was spent on teaching us to compute oxidation states of atoms in various compounds, following a set of rules that looked somewhat arbitrary to me at the time. As far as I remember, we were never told what benefits (other than passing tests) knowledge of oxidation states would give us. They were used as part of a convoluted procedure for "balancing redox reactions", but I never saw an example of that where it wouldn't give the same results simply to require that the number of nuclei of each element, as well as the total charge, must be the same on both sides of the reaction, and solve the resulting linear Diophantine equations. Nevertheless, the concept must be useful other than for setting homework exercises -- I see encyclopedias and other sources use much space on classifying compounds based on the oxidation state of this atom or that. Still I don't recall seeing any case where the oxidation states are used for anything (other than computing other oxidation states). What is this concept actually used for? Just a basic example or two where knowing the oxidation states helps produce a meaningful prediction. It doesn't seem that "oxidation state" actually encodes any particular configuration change inside the atom that tends to be preserved across reactions. Or does it somehow require effort (energy?) to change an atom from one oxidation state to another? In which case, what actually changes? Sorry if thi...

Recent Examples on the Web The difference lies in what chemists call the oxidation state, which indicates how reactive a substance is. — George Johnson, Discover Magazine, 25 Mar. 2013 The researchers found that a change in the oxidation state of the element chromium (from chromium 6 to chromium 3) was linked to the darkening of chrome yellow paint. — Andrew Moseman, Discover Magazine, 15 Feb. 2011 The work suggests that a few chemical treatments might help leach away some of the heavy metals and convert the iron into an oxidation state more similar to that seen in typical Earth soils. — John Timmer, Ars Technica, 12 May 2022 In addition, the vanadium ions can change their oxidation state during this process as well. — John Timmer, Ars Technica, 4 Sep. 2020 The color depends on the oxidation state of the iron atom bound to the muscle. — Popular Science, 1 Jan. 2019 These examples are programmatically compiled from various online sources to illustrate current usage of the word 'oxidation state.' Any opinions expressed in the examples do not represent those of Merriam-Webster or its editors.

When atoms are covalently bonded, they share electrons. Some atoms don't share as evenly as others, and when there's a big enough electronegativity difference they draw the shared electrons toward them more. There's a few ways of describing this, and hogging the electrons is a nice, simple way to do it. You can also say the bond has some ionic character, as one atom is partially stealing the electron. You can also say the more electronegative atom is withdrawing the charge from the less electronegative atom, exposing its nucleus and making it effectively a little bit positive. It is 36-38. The net gain from glycolysis is two molecules of ATP and two molecules of NADH. The conversion of pyruvate to acetyl CoA and its metabolism via the citric acid cycle yields two additional molecules of ATP, eight of NADH, and two of FADH2. Assuming that three molecules of ATP are derived from the oxidation of each NADH and two from each FADH2, the total yield is 38 molecules of ATP per molecule of glucose. Depending on the system used, this transfer may result in these electrons entering the electron transport chain at the level of FADH2. In such cases, the two molecules of NADH derived from glycolysis give rise to two rather than three molecules of ATP, reducing the total yield to 36 rather than 38 ATPs per molecule of glucose. Sal says that when carbon gains hydrogen, it is reduced, because carbon is much more electronegative than hydrogen, so it hogs the electrons. But I thought that h...

Definition of oxidation state for carbon As we begin to look at organic redox reactions, it is useful to consider how we define the oxidation state for carbon. Most of the redox reactions in this chapter involve a change in the oxidation state of the carbon bearing the functional group. To calculate the oxidation state for carbon, use the following guidelines: • In a C-H bond, the H is treated as if it has an oxidation state of +1. This means that every C-H bond will decrease the oxidation state of carbon by 1. • For carbon bonded to a more electronegative non-metal X, such as nitrogen, oxygen, sulfur or the halogens, each C-X bond will increase the oxidation state of the carbon by 1. (Certain non-metals are less electronegative than carbon, such as phosphorus, silicon or boron, but bonds from carbon to these elements are much less common.) • For carbon bonded to another carbon, the oxidation state is unaffected. So a carbon attached to 4 carbons has an oxidation state of zero. So unlike metals, which are almost always in a positive oxidation state, the oxidation state of carbon can vary widely, from -4 (in CH4) to +4 (such as in CO2). Here are some examples. (Don’t forget that this is called a “formalism” for a reason. The charge on the carbon is not really +4 or –4. But the oxidation state formalism helps us keep track of where the electrons are going, which will come in handy very soon). With an understanding of how to calculate oxidation states on carbon, we’re ready f...

Iridium is the only element known (and this was only recently demonstrated) to achieve the +9 oxidation state (in the cation IrO₄⁺). There are seven elements that can achieve +8 (Ru, Xe, Os, Ir, Pu, Cm and Hs). Since the results for the +9 oxidation state in Ir were first published just a few weeks ago (October 23, 2014) most sources you see will say that +8 is the highest oxidation state. The lowest known oxidation state is −4, which only Group 14 elements are known to achieve. First, keep in mind that oxidation numbers are NOT charges. The oxidation numbers are statements about what the charge on the atom would be if all of its bonds were 100% ionic. Thus, in Mg(OH)₂ you have two separate things going on. First you have O and H covalently bonded to each other with a negative charge (taken from Mg) and you have two sets of O and H. So, we have two OH⁻ anions. They got their extra electrons from the Mg, so Mg has a charge of +2, so it is a cation. Thus, the second thing occurring is that we have an ionic bond between Mg⁺² cation and the two OH⁻ anions. That is why we have Mg(OH)₂ Thus, the oxidation states in Mg(OH)₂ are Mg +2 O -2 H +1 My Chemistry teacher taught us to assume that Oxygen is 2-, and Hydrogen is 1+. You always know the Charge of the compound, such as HO 's charge is 1-. So if Oxygen is 2-, and Hydrogen is 1+, then the charge is 1-. For something like MgO, where the charge is neutral. You can assume that Oxygen is 2-, and so Mg must be 2+ to keep the compoun...

Both must occur together for it to be a redox reaction, but if only one occurred it would be called an "oxidation half-reaction" or a "reduction half-reaction." Finding these "half reactions" are often essential to solve a redox reaction problem, but they are NOT redox reactions themselves. I hope that helps! Hydrogen makes very few ionic compounds. If you want to think in terms of the octet rule, H would have no electrons whatsoever if it gave its electron to F. So, for H to achieve its full two electrons (remember that H seeks 2, not 8, electrons) then the only way to do that with F is by sharing the electron. Thus a polar covalent bond results in F and H both having what they want. And, in fact, all of the hydrogen halides in their pure form have polar covalent or covalent bonds. None is ionic. However, when dissolved in water to form acids, the chemistry is a bit different. HF is a weak acid and HCl, HBr, and HI are strong acids. So, it is rather usual for hydrogen to be involved in an ionic bond. There are a few such compounds (some of the hydrides are ionic), but it is unusual. I think I should note that some websites get this wrong. There is an article on eHow that really messes this up. Some mistakenly think that just because some compounds of hydrogen easily dissociate in water (the strong acids) then they must be ionic. But, this is not the case. There is a chemical interact between the hydrogen halides and water that allows all but HF to fully dissociate, but th...