3.11. Periodic Classification of Elements: Metals, non-metals and metalloids

The Periodic Classification of Elements is an extremely important tool for understanding Chemistry. It is a visual representation that organizes chemical elements into groups and periods, according to their physical and chemical properties. In this chapter, we'll focus on three main categories of elements in the periodic table: metals, nonmetals, and metalloids.

Metals:

Metals are the largest class of elements on the periodic table. They are located on the left and center of the table. Metals have several common properties. They are mostly solid at room temperature (with the exception of mercury), have a high melting and boiling point, are good conductors of heat and electricity, and are malleable and ductile, meaning they can be shaped or stretched. in threads without breaking.

Metals can be subdivided into several groups, including alkali metals, alkaline earth metals, transition metals, post-transition metals, lanthanides, and actinides. Each group has its own distinct properties. For example, alkali metals are very reactive and have only one electron in their outer shell, while transition metals are characterized by their ability to form colored complexes.

Non-metals:

Nonmetals are located on the right side of the periodic table. They have properties that are generally the opposite of those of metals. For example, nonmetals are generally poor conductors of heat and electricity, have relatively low melting and boiling points, and most are gases at room temperature. Nonmetals also tend to be more reactive than metals, as they have more electrons in their outer shell.

Nonmetals can be divided into several groups, including halogens and noble gases. Halogens are highly reactive and have seven electrons in their outer shell, while noble gases are notable for their low reactivity due to their full outer shell of electrons.

Metalloids:

Metalloids, also known as semimetals, are elements that have properties intermediate between those of metals and nonmetals. They are located on the diagonal line that separates metals from nonmetals on the periodic table. Metalloids include boron, silicon, germanium, arsenic, antimony, tellurium, and polonium.

Metalloids have some metallic properties and some non-metallic properties. For example, they can be shiny like metals, but brittle like non-metals. They are also semiconductors, which means they can conduct electricity under certain conditions but not others. This makes metalloids useful materials in many electronic devices.

In summary, the Periodic Classification of Elements is a crucial tool for understanding the properties of chemical elements and their interactions. Understanding the differences between metals, non-metals and metalloids is fundamental to understanding chemistry and is a topic that will certainly be addressed in the ENEM test.

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