Oxidation level call a conditional charge of atom in a molecule. At the same time assume that all communications have ionic character. In other words, oxidation level characterizes a possibility of an element to form ionic communication.
It is required to you
- - Mendeleyev's table.
Instruction
1. The sum of oxidation levels of atoms is equal in connection to a charge of this connection. Means, in simple substance, for example, Na or H2, the oxidation level of an element is equal to zero.
2. In connections with nonmetals the oxidation level of hydrogen is necessary equal +1, in connections with metals equal-1. An example - in SaH2 connection calcium - metal, oxidation level of atoms of hydrogen it is equal to-1. As the substance particle electroneutral, the oxidation level of calcium has to be equal (0-(-1))*2 = +2. Really, in the sum of oxidation level of calcium (+2) and two atoms of hydrogen (-1) give zero. Similarly, HCl is connection with nonmetal chlorine. Hydrogen oxidation level in this case is equal to +1. Then the oxidation level of atom of chlorine is equal to-1.
3. Oxygen oxidation level is usually equal in connections to-2. For example, in H2O water two atoms of hydrogen and one atom of oxygen. Really,-2+1+1 = 0 - in the left part expression there is a sum of oxidation levels of all atoms entering connection. In SaO calcium has the oxidation level +2, and oxygen-2. Exceptions of this rule are OF2 and H2O2 connections. At fluorine the oxidation level is always equal to-1.
4. Usually maximum positive oxidation level of an element coincides with number of its group in the periodic table of elements of Mendeleyev. The maximum negative oxidation level is equal to number of group of an element minus eight. An example - chlorine in the seventh group. 7-8 =-1 - chlorine oxidation level. The exception in this rule is made by fluorine, oxygen and iron - the highest oxidation level is lower than number of their group. At elements of subgroup of copper the highest oxidation level more than 1.