Non-metals are elements that differ significantly in physical and chemical properties from metals. The reason for their differences could be explained in detail only at the end of the 19th century, after the discovery of the electronic structure of the atom. What is the peculiarity of non-metals? What qualities are characteristic of their day? Let's find out.
Non-metals - what is it?
The approach to separating elements into metals and non-metals has long existed in the scientific community. The first elements in the periodic table of Mendeleev usually include 94 elements. Mendeleev's non-metals include 22 elements. In the periodic table, they occupy the upper right corner.
In free form, non-metals are simple substances, the main feature of which is the absence of characteristic metallic properties. They can be in all states of aggregation. So, iodine, phosphorus, sulfur, carbon are found in the form of solid substances. The gaseous state is characteristic of oxygen, nitrogen, fluorine, etc. Only bromine is a liquid.
In nature, non-metal elements can exist both in the form of simple substances and in the formconnections. Sulfur, nitrogen, oxygen are found in unbound form. In compounds, they form borates, phosphates, etc. In this form, they are present in minerals, water, rocks.
Different from metals
Non-metals are elements that differ from metals in appearance, structure and chemical properties. They have a large number of unpaired electrons at the outer level, which means they are more active in oxidative reactions and more easily attach additional electrons to themselves.
A characteristic difference between the elements is observed in the structure of the crystal lattice. In metals, it is metallic. In non-metals, it can be of two types: atomic and molecular. The atomic lattice gives substances hardness and increases the melting point; it is characteristic of silicon, boron, and germanium. Chlorine, sulfur, oxygen have a molecular lattice. It gives them volatility and a little hardness.
The internal structure of elements determines their physical properties. Metals have a characteristic luster, good conductivity of current and heat. They are hard, ductile, malleable, and have a small range of colors (black, shades of grey, sometimes yellowish).
Non-metals are liquid, gaseous or solid substances that do not have brilliance and malleability. Their colors vary greatly and can be red, black, gray, yellow, etc. Almost all non-metals are poor conductors of current (except carbon) and heat (except black phosphorus and carbon).
Chemical properties of nonmetals
In chemical reactions, non-metals canact as both oxidizing and reducing agents. When interacting with metals, they take on electrons, thus exhibiting oxidizing properties.
Interacting with other non-metals, they behave differently. In such reactions, the less electronegative element acts as a reducing agent, while the more electronegative element acts as an oxidizing agent.
With oxygen, almost all (except fluorine) non-metals act as reducing agents. When interacting with hydrogen, many are oxidizing agents, subsequently forming volatile compounds.
Some non-metal elements have the ability to form several simple substances or modifications. This phenomenon is called allotropy. For example, carbon exists in the form of graphite, diamond, carbine, and other modifications. Oxygen has two of them - ozone and oxygen itself. Phosphorus comes in red, black, white and metallic.
Nonmetals in nature
Nonmetals are everywhere in varying amounts. They are part of the earth's crust, are part of the atmosphere, hydrosphere, are present in the universe and in living organisms. In outer space, the most common are hydrogen and helium.
Within the Earth, the situation is quite different. The most important constituents of the earth's crust are oxygen and silicon. They make up more than 75% of its mass. But the smallest amount falls on iodine and bromine.
In the composition of sea water, oxygen accounts for 85.80%, and hydrogen - 10.67%. Its composition also includes chlorine, sulfur, boron, bromine, carbon,fluorine and silicon. Nitrogen (78%) and oxygen (21%) dominate in the composition of the atmosphere.
Non-metals such as carbon, hydrogen, phosphorus, sulfur, oxygen and nitrogen are important organic substances. They support the vital activity of all living beings on our planet, including people.
