Once the generalities of metals and non-metals were observed, it was known that the main differences between both groups revolve around the following properties:
- Valence electrons
- Chemical reactivity
- Melting point
- Boiling point
- Thermal conductivity
- Electric conductivity
- Water solubility
Therefore, the properties of metals and non-metals should be detailed separately.
Properties of metals
The metals are the elements that concentrate in several regions of the periodic table: left, in the center and the two periods (rows) lower ranging separately. Each of these regions is given a name by the type of metals that make it up:
- On the left: alkali metals, alkaline earth metals.
- In the center: transition metals.
- In the two lower periods: rare earths; a period for lanthanides and another for actinides.
Its properties are as follows:
- They are solid at room temperature, except for mercury (Hg), which is liquid.
- They have 1 to 3 valence electrons, so they are capable of delivering them in an ionic bond.
- Its atoms are organized with metallic bonds, forming very resistant geometric structures and with great cohesion forces.
- They have good electrical conductivity. If connected to a source, they are able to carry current from one point to another.
- They have good thermal conductivity. In contact with the sun or with the heat of a combustion, they tend to receive heat and transmit it or disperse it around them.
- When combined with water, they can generate oxides or hydroxides.
- They are generally a bright grayish color, although some may be opaque.
- If handled with progressive force, they are malleable and ductile. There are some that when receiving a sudden force or an impact are brittle.
- When heated enough, hundreds or thousands of degrees Celsius, they melt. This helps two or more of them mix to form alloys.
Properties of non-metals
The nonmetals are the elements that are positioned the right side of the periodic table, comprising several columns or groups. Each of them contains elements that are chemically similar to each other, forming the following families:
- Earth elements
- Carbon family
- Nitrogen family
- Oxygen family
- Noble gases
Its properties are as follows:
- They can be solid, liquid or gaseous at room temperature.
- If they are solid, they are very brittle.
- They are poor conductors of heat.
- They are poor conductors of electrical current.
- When they combine with water, they tend to form oxyacids.
You just have to pay attention to the symbology of the periodic table: there is an intermediate region that includes the so-called metalloids , elements that have properties of both metals and non-metals. The metalloids are: boron (B), silicon (Si), germanium (Ge), arsenic (As), antimony (Sb), tellurium (te), astate (At).
Examples of metals
Copper.- Chemical element with atomic number 29 and chemical symbol Cu , slightly reddish-brown golden color, bright. Its melting point is 1085 ° C and its density is 8.96 grams per cm3. It is one of the first metals handled by humanity. It is a good conductor of heat and electricity, very ductile and malleable, as well as being more or less abundant in the earth’s crust, which is why it is used to make wires and cables that conduct electricity. When oxidized, it forms a greenish layer.
Vanadium.- Chemical element with atomic number 23 and chemical symbol V, grayish-white in color. Its melting point is 1902 ° C and its density is 6.11 grams per cm3. It is a rare chemical element, and its main use is to make steel alloys, which give it greater hardness and sharpness, and it is mainly used to make tools that support torsion and cutting tools such as drills or burins.
Rhodium.- Chemical element with atomic number 45 and chemical symbol Rh , shiny silver. Its melting point is 1964 ° C and its density is 12.45 grams per cm3. It is a very rare metal, toxic to humans. However, it has been used in jewelry to maintain the brilliance of so-called white gold, as it forms a hard and oxidation resistant surface; however, because of its scarcity it is much more expensive than gold.
Osmium.- Chemical element with atomic number 76 and chemical symbol “ Os ”, greyish white and bright. Its melting point is 3033 ° C and its density is 22.60 grams per cm3. It is one of the heaviest natural chemical elements. It tends to form oxides easily, and is used primarily in chemistry as an oxidant in organic chemistry.
Polonium.- Chemical element with atomic number 84 and chemical symbol Po , grayish in color. Its melting point is 254 ° C and its density is 9.16 grams per cm3. It is a radioactive metal, which in its natural state is linked to another radioactive element: uranium. Despite being solid, from 54 ° C it is volatile, forming compounds and oxides with air. It is toxic and radioactive, and is used primarily in the space industry.
Carbon.- Chemical element with atomic number 6 and chemical symbol C, black or crystalline, depending on the molecular organization it presents. Its melting point is 3800 ° C and its density is 2.27 grams per cm3. It is one of the main compounds of living beings, and it is present in all cells and chemical compounds necessary for life. Chemical compounds derived from carbon and that have to do with biology, form a part of chemistry known as organic chemistry or carbon chemistry.
Phosphorus.- Chemical element with atomic number 15 and chemical symbol P, with a matt reddish or bright white color. Its melting point is 44 ° C and its density is 1.82 grams per cm3. It is also an important element for organic chemistry, as it is part of DNA, as well as the ATP molecule, which is the main transmitter of the energy that cells consume. It is also present in bones and teeth of living beings. Among the uses of inorganic chemistry and industry, its use in fertilizers and explosives stands out, since the white form ignites on contact with air.
Selenium.- Chemical element with atomic number 34 and chemical symbol Se, it is a solid with a crystalline gray color, which is the most common form, although there is also black or red crystalline, as well as a liquid form. Its melting point is 221 ° C and its density is 4.79 grams per cm3. Selenium is a micronutrient that helps slow aging processes and stimulates the immune system. Mixed with sulfur, it forms selenium sulfide, which is used as a medicine in soaps and shampoos to treat seborrheic dermatitis.
Bromine.- Chemical element with atomic number 55 and chemical symbol Br, it is a reddish, dense and volatile liquid. Its melting point is –7 ° C and its density is 3.12 grams per cm3. This element was also known as liquid fire, although in nature it is always found combined with other elements. Bromine is dangerous as it is irritating to living tissues, especially mucous membranes and eyes. Bromides have application in various industries, such as insecticides, the medical industry as an anesthetic and in photography, for film emulsions.
Iodine.- Chemical element with atomic number 53 and chemical symbol I, in its pure state it forms a violet-colored gas, and it also has a solid form, of a purplish-gray color, which is called metallic iodine or sublimated iodine, which in Contact with air and heat is converted back to diatomic iodine vapor. Its melting point is 114 ° C and its density is 1.93 grams per cm3. It is a very important micronutrient to regulate the function of the thyroid gland; its deficiency causes a thickening of this gland, known as goiter. In industry it is used as a reagent to detect starch and to manufacture antiseptics and disinfectants.
More examples of metallic elements:
- Lithium Li
- Sodium Na
- Potassium K
- Rubidium Rb
- Cesium Cs
- Silver Ag
- Ammonium ion NH3
- Beryllium Be
- Magnesium Mg
- Calcium Ca
- Strontium Sr
- Zinc Zn
- Cadmi Cdo
- Barium Ba
- Aluminum Al
- Bismuth Bi
- Copper Cu
- Mercury Hg
- Gold Au
- Iron Fe
- Cobalt Co
- Nickel Ni
- Chromium Cr
- Manganese Mn
- Lead Pb
- Tin Sn
- Platinum Pt
More examples of non-metallic elements:
- Hydrogen H
- Fluorine F
- Chlorine Cl
- Bromine Br
- Iodine I
- Oxygen O
- Sulfur S
- Selenium Se
- Tellurium Te
- Nitrogen N
- Phosphorus P
- Arsenic As
- Antimony Sb
- Boron B
- Carbon C
- Silicon Yes