Chemical reactions
Subject:
Chemistry [1]
Electrochemical reactions involve the transfer of electrons. Mass and charge are conserved when balancing these reactions, but you need to know which atoms are oxidized and which atoms are reduced during the reaction.?Oxidation numbers?are used to keep track of how many electrons are lost or gained by each atom. These oxidation numbers are assigned using the following rules: The convention is that the cation is written first in a formula, followed by the anion. For example, in NaH, the H is H-; in HCl, the H is H+. The oxidation number of a free element is always 0. The atoms in He and N2, for example, have oxidation numbers of 0. The oxidation number of a monatomic ion equals the charge of the ion. For example, the oxidation number of Na+?is +1; the oxidation number of N3-?is -3.