Phosphorus – the chemical element having the 15th serial number in Mendeleyev's Table. It is located in its V group. The classical nonmetal discovered by the alchemist Brand in the 1669th year. There are three main modifications of phosphorus: red (being a part of mix for ignition of matches), white and black. With very high pressures (about 8.3*10^10Па) black phosphorus passes into other allotropic state ("metal phosphorus") and begins to carry current. How to determine phosphorus oxidation level in various substances?
Instruction
1. Remember what is oxidation level. It is the size corresponding to an ion charge in a molecule provided that electronic couples which are carrying out communication are displaced towards more electronegative element (located in Mendeleyev's Table is more right and is higher).
2. It is necessary to know the main condition also: the sum of electric charges of all ions which are a part of a molecule taking into account coefficients always has to equal to zero.
3. It is necessary to remember that the oxidation level of the elements which are a part of simple substance (for example, C, O2, Cl2), is always equal to zero.
4. Oxidation level not always quantitatively coincides with valency. The best example – carbon which in organic molecules always has the valency equal 4 and oxidation level can be equal both-4, and 0, and +2, and +4.
5. What oxidation level of phosphorus in PH3 phosphene molecule, for example? Taking into account all aforesaid to give the answer to this question very easily. As hydrogen – the very first element in Mendeleyev's Table, it by definition cannot be located there "more to the right and above", than phosphorus. Therefore, phosphorus will attract to itself hydrogen electrons.
6. Each atom of hydrogen, having lost an electron, will turn into a positively charged ion with oxidation level +1. Therefore, the total positive charge is equal to +3. Means, taking into account the rule saying that the total charge of a molecule is equal to zero, phosphorus oxidation level is equal in a molecule of phosphene to-3.
7. Well, and what oxidation level of phosphorus in P2O5 oxide? Take Mendeleyev's Table. Oxygen is located in the VI group, it is more right than phosphorus, and besides above, therefore, unambiguously more elektrootritsatelen. That is oxygen oxidation level in this connection will be with the sign "minus", and phosphorus – with the sign "plus". What these degrees that the molecule in general was neutral? It is easily possible to see that the least common multiple for numbers 2 and 5 is 10. Therefore, oxygen-2 oxidation level, and phosphorus +5.