Use the rules (in order) to assign oxidation numbers to each of the elements in the compounds below. nitrosyl fluoride F N O

NOF

chlorine pentafluoride Cl F

ClF5

sulfurous acid H S O

H2SO3

The oxidation number is an integer that represents the number of electrons that an atom receives or makes available to others when it forms a given compound.

The oxidation number is positive if the atom loses electrons, or shares them with an atom that has a tendency to accept them. And it will be negative when the atom gains electrons, or shares them with an atom that has a tendency to give them up.

Chemical compounds are electrically neutral. That is, the charge that all the atoms of a compound contribute must be globally null. That is, when having positive or negative charges in a compound, their sum must be zero.

There are some rules for determining oxidation numbers in compounds. Among them it is possible to mention:

Hydrogen (H) has an oxidation number + 1 with nonmetals and - 1 with metals. Oxygen (O) presents the oxidation number - 2 Fluorine F has a unique oxidation state - 1

Then:

NOF: N + (-2) + (-1) = 0 → N=3 → oxidation number of nitrogen (N) is + 3, oxidation number of oxygen (O) is - 2 and oxidation number of fluorine (F) is - 1. ClF₅: Cl + 5 * (-1) = 0 → Cl = 5 → oxidation number of chlorine (Cl) is + 5 and oxidation number of fluorine (F) is - 1. H₂SO₃: 2 * (+1) + S+3 * (-2) = 0 → S=4 → oxidation number of hydrogen (H) is + 1, oxidation number of oxygen (O) is - 2 and oxidation number of sulfur (S) is + 4.