The logical continuation of the periodic law is 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 logical and scientifically substantiated.
The most important classes of inorganic compounds: salts, oxides, acids, bases (hydroxides).
The classification of substances greatly facilitates the process of studying them. 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 - compounds of elements with oxygen, in which the latter is attached to the atom of the element. In fact, all elements except three inert ones - Argon, Helium, Neon - form oxides.
Classes of Inorganic Compounds: Oxide Hydrates
The vast majority of oxides directly or directly form compounds with water, which are called oxide hydrates or hydroxides. The composition of the hydroxide 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 element, hydroxides are divided into hydrates of basic oxides (bases), hydrates of amphoteric oxides (amphoteric hydroxides), and hydrates of acid oxides (acids). The belonging of a 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 Oxygen on the one hand, and between Oxygen and Hydrogen on the other.
Classes of inorganic compounds: acids
Acids include chemical compounds consisting of several Hydrogen atoms, which are able to shift to a metal with the formation of salts. The group of atoms that remains after cleavage of the Hydrogen atoms from the acid molecule is called the acid residue.
Classes of inorganic compounds: salts
Salts are considered as products of partial or complete replacement of Hydrogen atoms by metal atoms or OH base groups by acid residues. In some cases, Hydrogen in acids can be replaced not only by a metal, but also by another group of atoms that have a positive charge (cation). Depending on the composition and properties of the salt are divided into the following types: acidic, basic, medium, complex.
Medium (normal) salts are formed due to the complete replacement of the Hydrogen atoms of acids by metal (cation), or hydroxyl groups in bases by acidic 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 interconnected in such proportions that the salt is electrically neutral.
Acid salts are obtained by incomplete substitution of Hydrogen atoms in acids by metal. Acid salts form only polybasic acids. The process of formulating acid salts remains the same as for medium salts: the charge of the cation and the acid residue is determined and these particles are interconnected in a ratio that does not violate the principle of electroneutrality of molecules.
Basic salts are obtained by incomplete substitution of OH groups of bases or amphoteric hydroxides with acid residues. The basic salt formulas consist of residues of multi-acid bases or amphoteric hydroxides that have partially lost hydroxyl groups and acid residues. As in all previous options, it is imperative to adhere to the principle of electroneutrality.