Chemical Properties of Matter
Chemical properties are the attributes and behaviors that matter has according to its chemical structure, that is, by the atoms that make it up and the bonds with which they are united. These properties are what tell how each substance interacts with others and carries out processes called chemical reactions, in which two or more materials are capable of transforming each other to create new and different ones that are called products.
In addition to describing how atoms or molecules behave during a reaction, chemical properties indicate what happens to them when they are exposed to certain amounts of energy. This is the case of ionization energy , for example, which expresses the amount of energy needed to remove 1 electron from the last shell of an atom in an element. Or the activation energy , which is the minimum amount of energy for a reaction to start happening.
The main chemical properties are:
- Oxidation or valence state
- covalent radius
- ionic radius
The chemical properties that make a substance dangerous due to its way of reacting are also added:
Read Also: Physics Properties
These five together with the Biological-Infectious hazard constitute the CRETIB characteristics, chemical properties that define a hazardous waste, according to the Official Standards.
Other chemical properties are quite simple and are based on the position of the chemical element within the Periodic Table of Chemical Elements. Among them are the so-called Periodic Properties, which are four:
- Atomic radio
- ionization energy
- Electronic affinity
15 Examples of Chemical Properties
- Oxidation state or valence: it is related to the number of electrons in the last shell of the element; it has a positive sign if it has between 1 and 4 and can give up those electrons during a chemical reaction.
- Covalent radius: in a covalent bond, it is the distance between the nucleus of one participating atom and the nucleus of the other.
- Ionic radius: in an ionic bond, it is the distance between the nucleus of one participating atom and the nucleus of the other.
- pH: or Hydrogen potential, is calculated as the antilogarithm of the concentration of hydrogen ions (H + ) in an aqueous solution. The scale of pH values goes from 1 to 14. Values from 1 to 6 are considered acidic pH . A pH of 7 is neutral . Values from 8 to 14 are considered alkaline or basic pH .
- Acidity: is the property of an aqueous solution with a pH less than 7, that is, between 1 and 6.
- Alkalinity: is the property of an aqueous solution with a pH greater than 7, that is, between 8 and 14.
- Corrosivity: it is the effect of attack or degradation that an acid or a base causes on a surface, which can be a metal, a non-metal or even human skin, so if the substance has this characteristic, it must be handled with care.
- Reactivity: is the ability of a substance to initiate a chemical reaction with another. The more reactive it is, the more energy it releases into the environment in the form of heat or the faster its environment cools.
- Explosiveness: This property is possessed by specific chemical substances, such as ammonium nitrate NH 4 NO 3 and trinitrotoluene (TNT). When receiving a spark or subjected to large amounts of heat, they react spontaneously and very quickly, releasing an enormous amount of energy in a very short time. Such a substance is very dangerous.
- Toxicity: is the property of substances that, when in contact with a living being, especially through ingestion and contact with the skin, alter its normal functions and cause diseases and internal injuries.
- Flammability: characterizes chemical substances that easily enter into a combustion reaction. These are mainly organic compounds.
- Atomic radius: it is the distance from the nucleus to the last electron shell of the same atom.
- Electronegativity: is the attraction that an atom can generate towards others. A more electronegative atom tends to attract others to form a bond. A less electronegative atom tends to be attracted.
- Ionization energy: is the energy required to remove an electron from the surface layer of an atom.
- Electron affinity: is the change in energy that occurs when an electron is added to the surface layer of an atom to convert it into a negative ion.