hapetuslukuna

Hapetuslukuna refers to the oxidation state of an atom in a molecule or ion. It is a bookkeeping tool used to track the number of electrons that have been lost or gained by an atom. The oxidation state is assigned based on a set of rules, and it is often a fractional value. The sum of the oxidation states of all atoms in a neutral molecule is zero. For polyatomic ions, the sum of the oxidation states equals the charge of the ion.

Common oxidation states include zero for elements in their elemental form, and positive values for metals that tend to lose electrons. Nonmetals often have negative oxidation states when combined with metals. For example, in sodium chloride (NaCl), sodium (Na) has an oxidation state of +1 and chlorine (Cl) has an oxidation state of -1. In water (H2O), oxygen (O) typically has an oxidation state of -2, and each hydrogen (H) has an oxidation state of +1.

Understanding oxidation states is crucial in redox (reduction-oxidation) reactions, where electrons are transferred between species. The species that loses electrons is oxidized (its oxidation state increases), and the species that gains electrons is reduced (its oxidation state decreases). For instance, in the reaction between zinc metal and copper(II) sulfate, zinc is oxidized from an oxidation state of 0 to +2, while copper is reduced from +2 to 0.