A logical continuation of the periodic lawis the classification of inorganic compounds. Like the classification of the elements themselves, the classification of chemical compounds is visually reflected in the periodic system and is, therefore, objectively natural and scientifically based.
The most important classes of inorganic compounds: salts, oxides, acids, bases (hydroxides).
Classification of substances greatly facilitatesprocess of their study. It is quite simple to characterize the properties of individual representatives of certain classes, if the typical chemical properties of the analyzed class are known.
Classes of inorganic compounds: oxides
Oxides are compounds of elements with Oxygen in which the latter is attached to the atom of the element. Virtually all elements except for the three inert gases - Argon, Helium, Neon - form oxides.
Classes of inorganic compounds: hydrates of oxides
The vast majority of oxides directly ordirectly form compounds with water, which are called oxides hydrates or hydroxides. The composition of the hydrocidide is expressed by the general formula E (OH) x, where E is the element that forms the hydroxide, x indicates the degree of oxidation in the corresponding oxide.
Depending on the chemical nature of the elementhydroxides are divided into hydrates of basic oxides (bases), hydrates of amphoteric oxides (amphoteric hydroxides), hydrates of acid oxides (acids). The affiliation of hydroxide to a certain class of compounds is determined by the location of the element in the periodic system, which determines the relative stability of the bonds between the element and the oxigen - on the one hand, and between Oxygen and Hydrogen - on the other.
Classes of inorganic compounds: acids
To acids include chemical compounds,consisting of several hydrogen atoms, which is capable of shifting to the metal to form salts. The group of atoms that has remained after cleavage from the molecule of the acid of the Hydrogen atoms is called the acid residue.
Classes of inorganic compounds: salts
Salts are considered as products of a partial orcomplete substitution of the Hydrogen atoms for metal atoms or OH groups of bases for acid residues. In some cases, the hydrogen in the acids can be replaced not only by the metal, but by another group of atoms that have a positive charge (cation). Depending on the composition and properties of the salt are divided into types: acidic, basic, medium, complex.
Average (normal) salts are formed due tocomplete substitution of the Hydrogen atoms of acids for the metal (cation), or hydroxyl groups in the bases for acid residues. The degree of oxidation of the metal and the charge of the acid residue must be known in order to be able to correctly formulate the formula of the average salt. They are combined among themselves in such proportions that the salt is electrically neutral.
Acidic salts are obtained with partial replacementHydrogen atoms in acids on a metal. Acidic salts form only polybasic acids. The process of composing the formulas of acid salts remains the same as for the middle salts: the charge of the cation and the acid residue is determined, and these particles are joined together in a ratio that does not violate the principle of electroneutrality of molecules.
Basic salts are obtained as a result of incompletesubstitution of OH groups of bases or amphoteric hydroxides for acid residues. The formulas for the basic salts consist of residues of multi-acid bases or amphoteric hydroxides that have partially lost hydroxyl groups and acid residues. As in all previous versions, it is necessary to adhere to the principle of electroneutrality.
