It is called a molecule to the union of two or more atoms by chemical bonds (of the same or different elements), forming a stable set. For example: the water molecule is H 2 0.
Molecules constitute the smallest division of a chemical without losing its physical-chemical properties or denaturalizing, and are usually electrically neutral (except for ions , which are positive or negative charge molecules).
The relationship established between the molecules of a substance give an account of its physical state: being close together, it will be a solid ; with mobility, it will be a liquid ; and being very dispersed without separating completely, it will be a gas.
Examples of molecules
|Water: H 2 0||Sucrose: C 12 H 22 O 11|
|Hydrogen: H 2||Propanal: C 3 H 8 O|
|Oxygen: O 2||Propenal: C 3 H 6 O|
|Methane: CH 4||Para-aminobenzoic acid: C 7 H 7 NO 2|
|Chlorine: Cl 2||Fluoride: F 2|
|Hydrochloric acid: HCl||Butane: C 4 H 10|
|Carbon dioxide: CO 2||Acetone: C 3 H 6 O|
|Carbon monoxide: CO||Acetylsalicylic acid: C 9 H 8 O 4|
|Lithium hydroxide: LiOH||Ethanoic acid: C 2 H 4 O 2|
|Bromine: Br 2||Cellulose: C 6 H 10 O 5|
|Iodine: I 2||Dextrose: C 6 H 12 O 6|
|Ammonium: NH 4||Trinitrotoluene: C 7 H 5 N 3 O 6|
|Sulfuric acid: H 2 SO 4||Ribose: C 5 H 10 O 5|
|Propane: C 3 H 8||Metanal: CH 2 O|
|Sodium hydroxide: NaOH||Silver nitrate: AgNO 3|
|Sodium chloride: NaCl||Sodium cyanide: NaCN|
|Sulfur dioxide: SO 2||Hydrobromic acid: HBr|
|Calcium sulfate: CaSO 4||Galactose: C 6 H 12 O 6|
|Ethanol: C 2 H 5 OH||Nitrous acid: HNO 2|
|Phosphoric acid: H 3 PO 4||Silica: SiO 2|
|Fullerene: C 60||Sodium thiopentate: C 11 H 17 N 2 O 2 SNa|
|Glucose: C 6 H 12 O 6||Barbituric acid: C 4 H 4 N 2 O 3|
|Sodium acid sulfate: NaHSO 4||Urea: CO (NH 2 ) 2|
|Boron trifluoride: BF 3||Ammonium chloride: NH 2 Cl|
|Chloroform: CHCl 3||Ammonia: NH 3|
Types of molecules
The molecules can be classified according to their atomic composition, namely:
Discreet . Constituted by a defined and punctual number of atoms, either of different elements or of the same nature. At the same time, classifiable according to the number of different atoms that are integrated into its structure, in:
- Monoatomic (1 same type of atom),
- Diatomic (two types),
- Trichotomous (three types),
- Tetralogical (four types) and so on.
Macromolecules or polymers . The macromolecules are large molecular chains made up of simpler pieces joined together, to form more complex constructions.
The model of traditional notation of molecules is expressed in relation to the present atomic content, by means of the symbols of the periodic table to represent the elements involved and a subscript that expresses the numerical relation of the same within the molecule.
However, since molecules are three-dimensional objects, a visual model that reflects the structure and not just the quantity of its elements is usually used for its complete understanding.