Oxidation Numbers

An element in which there are at least two almost equally energetic highest energy electrons can have more than one oxidation number, because some reagents will involve only one of these high energy electrons and other reagents or reaction conditions may involve more than one.

Oxidation refers to the process in which an atom loses electrons, causing an increase in its oxidation number. This results in the atom being oxidized, as it becomes more positively charged and forms a more positive oxidation state.

Oxidation is the process in which an atom loses electrons, resulting in an increase in its oxidation number. This occurs when an element undergoes chemical reactions where it loses electrons to become more positively charged. The oxidation number reflects the number of electrons that an atom has gained or lost in a compound.

2

They are written in roman numerals

The sum of the oxidation numbers in a compound is zero for a neutral compound. This is because the total positive oxidation numbers from the cations must equal the total negative oxidation numbers from the anions to balance out and form a neutral compound.

+1 in most of the compounds

-1 in metal hydrides

0 in elemental form

+3 in its compounds

Ag +1, O (2 x 3-), N 5 +

The oxidation numbers for H, O, and P in H3PO4 are +1, -2, and +5, respectively. This can be determined by assigning variable oxidation states to the atoms in the molecule based on known rules and maintaining overall charge neutrality.

The oxidation number of fluorine is -1. Fluorine is one of the most electronegative elements and tends to gain an electron to achieve a full outer shell, resulting in an oxidation number of -1 in most compounds.

The oxidation number of phosphorus in a hydrogen phosphate ion (HPO4^2-) is +5. This is because oxygen typically has an oxidation number of -2, and there are four oxygen atoms surrounding the phosphorus atom, giving it an oxidation number of +5 to balance the negative charge of the oxygens.

In Ni2O3, since oxygen has an oxidation number of -2 and there are three oxygen atoms, the total oxidation number contributed by oxygen is -6. Since the compound as a whole is neutral, the total oxidation number must be 0. Therefore, the oxidation number of nickel (Ni) in Ni2O3 is +3 to balance out the oxidation number from oxygen.

+6: Except in peroxides and superoxides, oxygen in compounds always has a formal oxidation number of -2, and hydrogen in salts or acid anions such as this has a formal oxidation number of +1. S must therefore have a value of +6 in this acid anion, to result in the total of -8 from four oxygen atoms and the +1 from hydrogen having a total charge of -1 for the acid anion.

The oxidation number of Li in Li2 is +1. Each Li atom has an oxidation number of +1 in ionic compounds.

0 in the elemental form, +2 or +4 in its compounds

In Na2S2O3, the oxidation numbers are +1 for sodium (Na), -2 for sulfur (S), and +2 for oxygen (O). This can be determined by considering the overall charge of the compound and known oxidation number rules.

The oxidation number of any element by itself is 0.

The answer is + 6

The way I figured it out was that O has a -2 charge.

-2 times 7 is - 14. to leave -2 you need a +12 charge.

So you divide 12 by 2 because you have 2 Cr and you get 6

Group 1 or alkali metals (+1 oxidation number).

Group 2 or alkaline earth metals (+2 oxidation number).

In N2O5, nitrogen has an oxidation number of +4 since it is more electronegative than oxygen and typically shows a range of -3 to +5. The oxidation number of oxygen in N2O5 is -2, since it is usually -2 in compounds, unless bonded to a more electronegative element.

The oxidation state of Cl in ClO2 is +3. This is determined by assigning oxygen an oxidation state of -2 and knowing that the overall charge of the compound is 0. Since there are two oxygen atoms with an oxidation state of -2 each, the oxidation state of Cl must be +3 to balance it out.

To figure this out, we first need to figure out the charge on S2O4.

We know that Na has a +1 charge, so the Na2 portion of the salt will have an overall +2 charge (2 x Na).

Provided that Na2S2O4 is a neutral molecule, we know that the charge of S2O4 must balance Na2, which has a +2 charge. Therefore, the charge on S2O4 is -2.

If the charge on S2O4 is -2, that must mean that there is an excess of 2 electrons in the molecule. We know that Oxygen usually has a charge of -2, and given that there are 4 Oxygen atoms in S2O4, the charge contributed by Oxygen is 4 x (-2) = -8. Since the charge of S2O4 is -2, we know that the total charge contributed by sulfur is +6.

+6 divided by 2 Sulfur atoms gives you the oxidation state (or number) of S: +3

(Definition of Valence, Valency in Chemistry: a property of atoms or radicals; their combining power given in terms of the number of hydrogen atoms (or the equivalent))

Valence is the number of bonds an atom can form. Hydrogen (H) always has valence 1, so other elements' valences equal the number of hydrogen atoms they combine with. Thus, oxygen (O) has valence 2, as in water (H2O); nitrogen (N) has valence 3, as in ammonia (NH3); and chlorine (Cl) has valence 1, as in hydrochloric acid (HCl).

The valence depends on the number of unpaired electrons in the outermost (and, in transition-elements, the next) shell of the atom's structure. The sharing of the unpaired (valence) electrons in a bond mimics the stable configuration of the noble-gases, whose outer shells are full. Elements that can achieve stable configurations by various combinations have more than one valence.

The central atom in this molecule is chlorine. It is bonded with two oxygen atoms and a hydrogen atoms. The oxidation number of chlorine is +3: four covalent bonds with oxygen yields +4 and the bond with hydrogen yields -1.