Chemical elements

Content

• Periodic table of elements
• Features and data
• Examples of chemical elements

Thechemical elements They are substances that by no means can be reduced or decomposed into other simpler substances. For this reason, it can be said that an element is all matter made by atoms of the same and unique class.

The first definition of chemical element was introduced by Lavoisier in the Traite Élémentaire de Chimie, in 1789. Back in the 18th century, Lavoisier subdivided simple substances into four groups:

1. Elements of bodies;
2. Non-metallic oxidizable and acidifiable substances;
3. Oxidizable and acidifiable metallic substances, and ...
4. Salidifiable earthly substances.

Periodic table of elements

Today 119 chemical elements are known, which are divided into a total of 18 groups and 7 periods. All of these elements are brought together in a graphic scheme known as the Periodic Table of the Elements, which was originally created by the Russian chemist Dimitri Mendeleyev in 1869.

The main groups that can be found in this table are the alkali metals, the alkaline earth metals, the transition metals (which is the most numerous group), the post-transition metals, the metalloids, the no metals (Fundamental elements for life are located here, such as oxygen and nitrogen), halogens, Noble gases, and finally, there are two quite particular groups of elements, the lanthanides and the actinides, which are sometimes referred to generically as rare earths (although some are relatively abundant).

Many of these elements have radioactive isotopes. Chemical elements have characteristic properties such as the point of boiling and that of fusion, electronegativity, density and ionic radius, among others. These characteristics are important because they allow predicting its behavior, reactivity, etc.

Features and data

Each chemical element appears characterized by several components. First of all, it highlights its universal symbol, consisting of one or two letters (by convention, if there are two letters, the first is written in uppercase and the next in lowercase).

Above and to the left appears in small typeface suatomic number, which is the one that indicates the amount of protons that this element has. Then the full name of the element and below this a number indicating the atomic mass in grams per mole.

The different elements present variable atomic volumes, and as the number of protons in the nucleus increases, the greater the attraction that this exerts on the electrons, so the volume tends to decrease. When the atomic volume is small, the electrons at the outermost level of the cloud are very attracted to the nucleus, so they do not give up easily. The opposite happens with elements with high atomic volumes: they give up their outer electrons easily.

Examples of chemical elements

It can serve you:

• Examples of Chemical Compounds
• Examples of Chemical Reactions
• Examples of Chemical Phenomena
• Examples of Metals and Non-Metals