All chemical elements can conditionally be divided into non-metals and metals. Do you know what signs they differ in? How to determine their position in the table of chemical elements? You will find answers to these and other questions in our article.
The position of non-metals and metals: the periodic table
By external signs and physical properties, it is not always possible to find out which group a chemical element belongs to. The properties of metals and non-metals can be determined by the location in the periodic table.
To do this, visually draw a diagonal from boron to astatine, from 5 to 85 numbers. In the upper right corner, non-metals will mainly be located. There are a minority of them in the table, only 22 elements. Metals are on the right side of the periodic table above - mainly in groups I, II and III.
Energy level
The differences between non-metals and metals are initially due to the structure of their atoms. Let's start with the number of electrons on the external energy level. For metal atoms, it varies from one to three. As a rule, they have a large radius, so metal atoms give away external electrons quite easily, since they have strong reducing properties.
In non-metals, the number of electrons at the external level is greater. This explains their oxidative activity. Non-metals attach the missing electrons, completely filling the energy level. The strongest oxidizing properties are exhibited by non-metals of the second and third periods of groups VI-VII.
The filled energy level contains 8 electrons. Halogens with valency I have the greatest oxidizing ability. Among them, fluorine is in the lead, since this element has no free orbitals.
The structure of metals and nonmetals: crystal lattices
The physical properties of substances are determined by the arrangement of elementary particles. If we conditionally connect them with imaginary lines, we get a structure called a crystal lattice. Its nodes may contain different structures: atoms, molecules or charged particles - ions.
In some non-metals, an atomic crystal lattice is formed, the particles of which are connected by covalent bonds. Substances with such a structure are solid and non-volatile. For example, phosphorus, silicon and graphite.
In a molecular crystal lattice, the bond between elementary particles is weaker. Typically, such non-metals are in a liquid or gaseous state of aggregation, but in some cases they are solid fusible non-metals.
In any metal sample, part of the atoms lose external electrons. In this case, they turn into positively charged particles - cations. The latter again combine with electrons, forming neutrally charged particles - cations, electrons and atoms are simultaneously in the metal lattice.
Physical properties
Let's start with the state of aggregation. It is generally accepted that all metals are solids. The only exception is mercury, a viscous liquid of silver color. Its pairs are a contaminant - a toxic substance that causes poisoning of the body.
Another characteristic feature is the metallic luster, which is explained by the fact that the surface of the metal reflects light rays. Another important feature is electrical and thermal conductivity. This property is due to the presence of free electrons in metal gratings, which begin to move in an electric field in a directional direction. It conducts heat and current mercury best of all, silver has the lowest rates.
Metallic bond determines ductility and ductility. According to these indicators, gold is the leader, from which it is possible to roll out a sheet thick in human hair.
Most often, the physical properties of metals and nonmetals are opposite. So, the latter are characterized by low indicators of electrical and thermal conductivity, lack of metallic luster. Under ordinary conditions, non-metals are in a gaseous or liquid state, while solid ones are always fragile and fusible, which is explained by the molecular structure of non-metals. Diamond, red phosphorus and silicon are refractory and non-volatile, these are substances with a non-molecular structure.
What are semimetals
In the periodic table between metals and non-metals there are a number of chemical elements that occupy an intermediate position. They are called semimetals. Atoms of semimetals are linked by a covalent chemical bond.
These substances combine the attributes of metals and non-metals. For example, antimony is a crystalline substance of silver-white color and reacts with acids to form salts - typical metallic properties. On the other hand, antimony is a very fragile substance that cannot be forged, and it can even be crushed by hand.
So, typical non-metals and metals have opposite properties, but the division is rather arbitrary, since a number of substances combines both of these signs.