Chemical compounds. In Chemistry , a compound is a substance formed by the union of two or more elements of the periodic table . An essential feature is that it has a chemical formula . For example, lime is a compound made up of calcium and oxygen in the ratio of 1 to 1 (in number of atoms ).
In general, this fixed ratio is due to an intrinsic property. A compound is made up of molecules or ions with stable bonds and does not obey arbitrary human selection. For this reason, bronze or chocolate are called mixtures or alloys , but not compounds.
The elements of a compound cannot be divided or separated by physical processes ( decantation , filtration , distillation , but only by chemical processes .
Summary
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- 1 Nature of chemical compounds
- 1 Links
- 2 Formula
- 3 Classification
- 4 Sources
Nature of chemical compounds
Links
The atoms in the molecule can remain unbound without links . There are two types of bonds: the covalent bond between atoms, an example is water that is linked by a polar covalent bond; and the ionic bond is between ions, such as sodium chloride .
There are some exceptions represented by H 2 , it is homonuclear , that is, it has single element atoms.
Formula
Chemists describe compounds using the chemical symbols for bonded atoms . The order of these in inorganic compounds ranges from the most electronegative to the right. For example in NaCl , the chlorine that is more electronegative than sodium is on the right side. There are several other rules for organic compounds.
Classification
The main chemical compounds that exist today are:
- Basic oxides , which are made of metal and oxygen. Examples: leaded oxide, lithium oxide.
- Acid oxides , formed by a non-metal and oxygen . Examples: hypochlorous oxide , selenious oxide .
- Hydrides , which can be both metallic and non-metallic. They are composed of an element and hydrogen. Examples: aluminum hydride , sodium hydride .
- Hydracids are non-metallic hydrides that, when dissolved in water, acquire an acid character. For example, hydroiodic acid ,.
- Hydroxides , compounds formed by the reaction between a basic oxide and water, which are characterized by having the oxydryl (OH) group. For example, sodium hydroxide , or caustic soda .
- Oxo acids , compounds obtained by the reaction of an acid oxide and water. Its molecules are made of hydrogen, a nonmetal, and oxygen . For example, chloric acid .
- Binary salts , compounds formed by a hydrazide plus a hydroxide. For example, sodium chloride.
- Oxisalts , formed by the reaction of an oxacid and a hydroxide, such as sodium hypochlorite.
