Oxidationsgrad

Oxidationsgrad, or oxidation state, is a formal concept in chemistry used to describe the degree of oxidation of an atom within a compound. It serves as a bookkeeping number that helps track electron transfer during redox reactions and provides a way to compare different oxidation environments across elements and compounds. The sum of all oxidation states in a neutral molecule is zero; in a polyatomic ion, it equals the ion’s charge.

Rules for assigning oxidation states are a practical convention. An element in its standard state has oxidation state 0. A monoatomic ion has an oxidation state equal to its charge. The sum of oxidation states in a neutral compound is 0; in a polyatomic ion, it equals the ion’s charge. Hydrogen is usually assigned +1 (except in metal hydrides, where it is -1). Oxygen is typically -2 (except in peroxides, where it is -1, and in compounds like OF2, where it is +2). Fluorine is always -1 in compounds; other halogens are usually -1 unless bonded to more electronegative elements. Alkali metals have +1; alkaline earth metals have +2.

Common examples illustrate the idea. In H2O, hydrogen is +1 and oxygen is -2. In CO2, carbon is +4 while each oxygen is -2. In NaCl, sodium is +1 and chlorine is -1.

Uses and interpretation: Oxidation states identify which species are oxidized or reduced in a reaction, guiding the balancing of redox equations through half-reaction methods. They are a formal accounting device; actual electron density can be delocalized, and certain systems may exhibit fractional or ambiguous oxidation states.

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