All known matter is made up of atoms, from the 118 chemical elements that make up the periodic table. One of the classifications of these elements is in metals and non-metals, according to its nature and its properties.
Almost all elements are metallic, generally derived from minerals and with electrical properties and interactions that have been thoroughly studied by inorganic chemistry. On the other hand, the rest of the elements, the non-metallic ones, are necessary for life and make up the different forms of known organic matter, although some metals are also part of organic molecules and play an important role in living organisms.
Differences between metals and non-metals
Metals and non-metals differ in their fundamental properties and their types of possible reactions.
- Metals. They are solid at room temperature, with the exception of mercury. They are glossy, more or less ductile and malleable, and are good conductors of electricity and heat. In contact with oxygen or acids, they oxidize and corrode (loss of electrons). They are less electronegative and have lower ionization energy than nonmetals. For instance: aluminum, lead, sodium.
- No metals. They tend to be poor conductors of electricity and heat, of very varied appearances and melting points generally well below metals. Many exist by forming molecules, such as molecular oxygen (O2) or dichlor (Cl2). They can be soft like sulfur or hard like diamond and can be found in any of the three states of matter: gaseous, liquid and solid. In addition, their appearance does not usually reflect light and they can have different colors. For instance: helium, chlorine, iodine.
Finally, metallic elements usually interact electrostatically with non-metallic ones to form ionic bonds, from which chemical compounds such as salts arise. Non-metallic ones, on the other hand, tend to form complex molecular structures through bonds of various kinds (covalent bonds, hydrogen bonding interactions, peptide bonds, etc.). Hence, organic or life chemistry is based on the latter, although living bodies are made up of combinations of both types of elements.
Examples of metals
- Iron (Faith). Also called ironIt is one of the most abundant metals in the earth’s crust, which makes up the heart of the planet, where it is in a liquid state. Its most striking property, apart from its hardness and relative ductility, is its great ferromagnetic capacity. Through alloying it with carbon it is possible to obtain steel.
- Magnesium (Mg). It is a very abundant element on earth, both in its crust and dissolved in the seas. It never occurs in nature in its pure state, but as ions forming salts. It is essential for life, usable for alloys and highly flammable.
- Gold (Au). It is a soft, shiny yellow precious metal that does not react with most chemicals except cyanide, mercury, chlorine, and bleach. Throughout history it played a vital role in human economic culture, as a symbol of wealth and support for currencies.
- Silver (Ag). Another of the precious metals is white, bright, ductile and malleable, it is in nature as part of various minerals or as pure leaves of the element. It is not very common in the earth’s crust. It is the best conductor of heat and electricity known.
- Aluminum (To the). It is a very light, non-ferromagnetic metal, the third most abundant in the earth’s crust. It is highly valued in the industrial and iron and steel trades, since through alloys it is possible to obtain variants of greater resistance but that retain their versatility. It has a low density and very good resistance to corrosion.
- Nickel (Neither). It is a very ductile and very malleable white metal, a good conductor of electricity and heat, as well as being ferromagnetic. It is one of the dense metals, along with iridium, osmium, and iron. It is vital for life, as it is part of many enzymes and proteins.
- Zinc (Zn). It is a transition metal similar to cadmium (Cd) and magnesium (Mg), often used in galvanizing processes, that is, as a protective coating for other metals. It is very resistant to cold plastic deformation, which is why it is worked above 100 ºC.
- Lead (Pb). It is widely used as a shield to avoid human contact with radioactive emissions. It is a very particular element, given its unique molecular flexibility, its ease of melting and its relative resistance to strong acids such as sulfuric or hydrochloric.
- Tin (Sn). It is a heavy and easily oxidized metal, used in many alloys to provide resistance to corrosion. When bent, it produces a very characteristic sound that has been dubbed the “tin cry.”
- Sodium (Na). It is a soft, silvery alkali metal present in sea salt and in the mineral called halite. It is highly reactive, oxidizable, and reacts exothermically and violently when mixed with water. It is one of the vital components of known living organisms.
Examples of non-metals
- Hydrogen (H). It is the most common and abundant element in the universe. It is a gas that is found both in the atmosphere (as a diatomic molecule H2 as being part of the vast majority of organic compounds, and also in the heart of the stars, where fusion occurs between the nuclei of this element. It is also the lightest element on the Periodic Table. On the other hand, it is odorless, colorless and insoluble in water.
- Oxygen (OR). It is essential for life, used by animals for their processes of obtaining energy (respiration). This gas (O2) is highly reactive and forms oxides with almost all the elements of the periodic table except the noble gases. It forms almost half the mass of the earth’s crust and is vital for the formation of water (H2OR).
- Carbon (C). It is the central element of all organic chemistry, common to all known living beings and part of more than 16 million compounds that require it. It is found in nature in two different forms: graphite and diamond, which have a structure based on carbon atoms, but arranged in different ways. Together with oxygen it forms carbon dioxide (CO2) essential for photosynthesis.
- Sulfur (S). It is a soft, abundant element with a characteristic odor, common to the activity of almost all living organisms and abundant in volcanic contexts. It is yellowish and insoluble in water, essential for organic life and extremely useful in industrial processes.
- Match (P). Despite never being in its native state in nature, it is an indispensable part of many organic compounds and living beings, such as DNA and RNA, or ATP. It is very reactive and when in contact with oxygen it emits light.
- Nitrogen (N). It is a normally diatomic gas (N2) that constitutes 78% of the air in the atmosphere and is present in numerous organic substances such as ammonia (NH3), despite being a low reactivity gas compared to hydrogen or oxygen.
- Helium (He). It is the second most common element in the universe, which can also be obtained as a product of the nuclear fusion of hydrogen in stars. It is a noble gas, that is to say, with almost zero reactivity, colorless, odorless and very light, often used as an insulator or as a refrigerant, in its liquid form.
- Chlorine (Cl). Chlorine in its purest form is a highly toxic yellowish gas (Cl2) with an unpleasant odor. However, it is abundant in nature and is part of many organic and inorganic substances, many of which are essential for life. Together with hydrogen, it forms hydrochloric acid (HCl), one of the most powerful acids that exist.
- Iodine (I). It is an element of the group of halogens, little reactive and electronegative. Despite this, it is used in medicine, in the photographic arts, and as a coloring agent. Despite being a non-metal, it has curious metallic characteristics and is reactive to mercury and sulfur.
- Selenium (I know). It is insoluble in water and alcohol, but soluble in ether and carbon disulfide, this element has photoelectric properties (it converts light into electricity) and is a necessary part of the manufacture of glass. It is also a nutrient for all forms of life, essential for many amino acids and present in many foods.