In order to determine the possible values of the valence of oxygen should examine the situation of the element in the periodic table, the main features of the structure of its atoms.This approach is useful in the study of the question of how the valence of oxygen at the typical and which is uncharacteristic for him.The most common compounds exhibit normal valency - II.This feature allows you to define the number of links to other atom finished binary formulas involving oxygen.
What have the valence of oxygen?
Initially, the accumulation of knowledge about the properties and structure of materials chemists thought that the valence - is the ability to bind a certain number of atoms in a molecule of a substance.Many scientists after the discovery of the element have tried to understand what the valence from oxygen.Response was obtained by experiment: oxygen attaches to the chemical reaction, two hydrogen atoms of a monovalent, means divalent.Notions of chemical bond changed with the accumulation of knowledge about the structure of matter.In his theory of valence G. Lewis and W. Kossel disclose the nature of the chemical interaction in terms of the electronic structure.Researchers attributed the ability of an atom to the formation of a certain number of connections to the desire of the most sustainable energy.In the case of achieving the smallest particle of matter becomes more stable.In theory, Lewis structures and a lot of attention paid to the role of external electrons participating in the creation of a chemical bond.
Properties of oxygen in the periodic table
In order to determine which have the valence of oxygen, it is necessary to consider some features of its electronic structure.Oxygen is headed by a group 16 of the periodic table.Common name of the family members - "chalcogens" of outdated classification they belong to VI (A) group.In the periodic table is the oxygen in the cell under №8.The core comprises in its composition 8 and the same number of positive neutral elementary particles.In the space of an atom there are two energy levels, which occur when driving 8 electrons, 6 of which - outside.
What relationship exists between the composition of the atom and the valence?
On the last level of the oxygen atom contains two unpaired electrons.The element fluorine is inferior in importance electronegativity (ability to attract bonding electrons pair).In the formation of the compounds with other elements oxygen attracts arisen in the molecule a total electron density (electrons except fluorine).Achieving steady state the outer sheath is possible when adding two negative charges.This means that oxygen need 2 electrons.The following options: accept one electron (valence II), away from the other two electron atom (valence II), not to accept electrons from other atoms (valence 0).Typical behavior of oxygen characterizes the second case.This way you can use to find out which have the valence of oxygen in its most typical common connections.These include a majority of oxides of metals and non-metals.
How does the valence in compounds?
Oxygen is able to directly interact with many chemical elements.Known to his connections with almost all representatives of the periodic table (except the inert gases argon, helium, neon).The reaction with halogens and noble metals, oxygen can not directly engage, but oxides Au2O3, F2O, Cl2O7 and others exist (indirectly obtained).For binary compounds in the formation of which involved oxygen, characterized by a covalent bond and polarity.Valence in such molecules depends on the number of pairs of electrons arising, which are attracted to the nucleus of different atoms.The vast majority of the compounds of oxygen atoms are involved in the creation of two covalent bonds.For example, CO2 oxides, P2O5, SO2, SO3, K2O, B2O3, and Mo2O5 in other molecules.The cation hydronium H3O + oxygen exhibits atypical for a valence of III.The presence of peroxo -OO- due to the unusual nature of the hydrogen peroxide H2O2.In this connection the oxygen exhibits his characteristic valence of II.
How to determine the valence of the elements?
idea of stretching the possibilities of oxygen gives the structure of Lewis - the chemical element symbol around which electrons points mark the outer layer.They take part in the creation of molecules that are part of the shared electron pairs.Lewis formula demonstrates the valence of oxygen corresponding to the number of its unpaired electrons (2).The same result gives the usage of graphic electronic structures.The two cells of the external oxygen levels are located unpaired electrons (indicated by arrows in the formula).For information about what the valence at the oxygen it possible to determine the final formula for the binary compound value of neighboring atoms.To conduct this simple calculations.First, multiply the number of O atoms to the normal rate for the oxygen valence.The resulting value is to be divided by the index as specified in the formula with the chemical symbol near another element in combining with oxygen.Using a simple method calculate a valence of carbon and phosphorus in their oxides.
- multiply the index at the bottom right of the sign About dioxide CO2 typical valence of the elements: • 2 2 = 4. The resulting number to divide the index specified for carbon: 4/1 = 4. Carbon dioxide CO2 is at its highest valence stateIV.
- index at the bottom right of the chemical symbol for oxygen in the phosphorus oxide P2O5 multiply the typical valence of the atom A: 5 • 2 = 10. This number will divide the specified index in the formula at the bottom right of the phosphorus atoms: 10/2 = 5. In the phosphorus oxide isable to its highest valence V.