Examples of non-metals
Examples of non-metals
All the elements classified as non-metals are:
- Hydrogen (H)
- Carbon (C)
- Nitrogen (N)
- Phosphorus (P)
- Oxygen (O)
- Sulfur (S)
- Selenium (Se)
- Fluorine (F)
- Chlorine (Cl)
- Bromine (Br)
- Iodine (I)
Hydrogen (H)
Hydrogen is the first element. It is by far the most abundant element in the universe . It combines with oxygen to form water H 2 O, the most abundant compound on planet Earth, which covers three-quarters of its surface. In addition, due to the constant evolution of technology, it is becoming an important fuel.
It occurs as a diatomic gas H 2 , whose chemistry is very different from that of the alkali metals that go under it, forming group IA on the periodic table. Because hydrogen, like fluorine and chlorine, needs an extra electron to fill an energy level, certain tables show it near the ice, on top of the fluorine, without looking like halogens.
The properties of this element are:
- Atomic number: 1
- Atomic weight: 1 g / mol
- Molecular weight (H 2 ): 2 g / mol
- Density: 0.0899 kg / m 3
- Electronegativity: 2.2
- Melting point: -259 ° C
- Boiling point: -523 ° C
Carbon (C)
Carbon is the element that heads the VAT group, and it is non-metallic. It comes in different ways called allotropes, or allotropic forms . These are charcoal, diamond, and graphite. The charcoal is a non – crystalline allotropic form of carbon without a defined atomic distribution.
The diamond is the allotrope of carbon with a very compact crystalline structure, which makes it one of the hardest materials. It is used to make tips for lathes. The graphite is the allotrope of carbon having a more subtle than that of the diamond structure. It is brittle and is used to make pencil tips.
In the mid-1980s a new allotropic form of carbon was discovered, with 60 atoms distributed similar to the surface of a soccer ball. These spheres of C 60 are often called buckyballs . As early as 1997, some scientists reported producing honeycomb-shaped carbon structures called nanotubes .
The properties of this element are:
- Atomic number: 6
- Atomic weight: 12 g / mol
- Density: 2267 kg / m 3
- Electronegativity: 2.55
- Melting point as Diamond: 3549.85 ° C
- Melting point as Graphite: 3526.85 ° C
- Boiling point as Graphite: 4826.85 ° C
Nitrogen (N)
Nitrogen is the element that heads the VA group of the periodic table. It is a gas with a diatomic molecule (N 2 ), and it comprises 78% of the air in the atmosphere . Both this and phosphorus are essential for life. Nitrogen molecules in the air are not very reactive; they are even considered inert.
However, certain bacteria in the soil can “fix” nitrogen, converting the compound into ammonia, which can be taken up by plant roots. On an industrial scale, nitrogen gas N 2 is combined with hydrogen gas H 2 to produce gaseous ammonia, NH 3 , which is used as a fertilizer and also in the manufacture of nitric acid and various explosives.
The properties of this element are:
- Atomic number: 7
- Atomic weight: 14 g / mol
- Molecular weight (N 2 ): 28 g / mol
- Density: 1.2506 kg / m 3
- Electronegativity: 3.04
- Melting point: -210 ° C
- Boiling point: -196 ° C
Phosphorus is a reactive solid that is not free in its natural state. An allotropic form of phosphorus is a red-violet, non-crystalline material that was once used to make matches or matches. Another allotropic form, of formula P 4 , has a yellowish-white , crystalline, waxy appearance .
It is necessary to keep it immersed in water to avoid its spontaneous combustion with the oxygen in the air. Phosphorous is used in the manufacture of matches, smoke bombs, tracer bullets, pesticides, and many other products. Phosphoric acid H 3 PO 4 is used in various carbonated beverages and to prepare other chemicals.
The properties of this element are:
- Atomic number: 15
- Atomic weight: 31 g / mol
- Density: 1823 kg / m 3
- Electronegativity: 2.19
- Melting point: 44 ° C
- Boiling point: 277 ° C
Oxygen (O)
Oxygen is the element that heads the group VIA of the periodic table. In its gaseous form, it is presented as a diatomic molecule (O 2 ). It constitutes 21% of the air in the atmosphere , and is essential for life and to sustain combustion reactions. The fuels that react with it are capable of burning, delivering a large amount of energy.
This gas is an allotropic form called ozone O 3 , formed by three oxygen atoms in the form O – O = O . Between two of them, there is a single bond, and at the other end there is a double bond. For the ozone molecule is stable, this double bond alternates between first and second positions, being O – O = O and O = O – O .
This phenomenon of double bond alternation is called resonance . It is this that allows the sun’s ultraviolet rays to be retained, so that they do not pass through the atmosphere to the earth’s surface.
The properties of this element are:
- Atomic number: 8
- Atomic weight: 16 g / mol
- Molecular weight (O 2 ): 32 g / mol
- Density: 1,429 kg / m 3
- Electronegativity: 3.44
- Melting point: -223 ° C
- Boiling point: -183 ° C
Sulfur (S)
Sulfur is the second nonmetal in group VIA. At room temperature it is a pale yellow solid that is free in its natural state. Sulfur molecules contain eight sulfur atoms attached in an S 8 ring . It is important in the manufacture of rubber tires and sulfuric acid H 2 SO 4. Sulfur compounds are important for bleaching fruits and grains.
When food decomposes in a shortage of oxygen, hydrogen sulfide H 2 S is produced, the gas responsible for the rotten egg smell. Sulfur is a nonmetal found in combination with metals in salts called sulfides . With iron it forms the ferrous FeS and ferric Fe 2 S 3 sulfides .
The properties of this element are:
- Atomic number: 16
- Atomic weight: 32 g / mol
- Density: 1960 kg / m 3
- Electronegativity: 2.58
- Melting point: 115 ° C
- Boiling point: 445 ° C
Selenium (Se)
Selenium is a non-metal with interesting properties and uses. The electrical conductivity of this element increases with the intensity of light. Because of this photoconductivity, selenium has been used in light meters, cameras, and photocopiers , but concerns about its toxicity have reduced its use.
Selenium also converts an alternating electrical current into direct current , which is why it has been used in rectifiers, such as converters that recharge portable radios and power tools. The red color that selenium contributes to glass is useful in the manufacture of lenses for traffic light signals .
The properties of this element are:
- Atomic number: 34
- Atomic weight: 78.97 g / mol
- Density: 4790 kg / m 3
- Electronegativity: 2.48
- Melting point: 221 ° C
- Boiling point: 685 ° C
Fluorine (F)
Fluorine is the leading non-metal in Group VIIA, also called the “halogen family”. This element has a diatomic molecule (F 2 ), and is the most electronegative of all , which is why it takes priority over other non-metals, to combine with metals. For example, sodium fluoride NaF is more likely to form than sodium chloride NaCl.
It is a pale yellow gas and the most non-metallic element of all. Many of their reactions result in explosions or fire. Wood and rubber spontaneously ignite in gaseous fluorine.
The properties of this element are:
- Atomic number: 9
- Atomic weight: 19 g / mol
- Molecular weight (F 2 ): 38 g / mol
- Density: 1,696 kg / m 3
- Electronegativity: 3.98
- Melting point: -220 ° C
- Boiling point: -188 ° C
Chlorine (Cl)
Chlorine is one of the most reactive non-metals. It is a greenish-yellow gas with an irritating odor. It combines with metals to form salts called chlorides, and with the vast majority of elements to form a wide variety of chemical compounds. It has an enormous oxidizing power, which is why it is used for disinfection processes.
The most commonly used chlorine compounds are sodium chloride NaCl , also known as table salt, which is responsible for intensifying the flavors of food. The sodium hypochlorite NaClO is one of the most resorted disinfectants in cleaning baths and purification of water. The hydrogen chloride or hydrochloric acid HCl is also used for disinfecting baths.
The properties of this element are:
- Atomic number: 17
- Atomic weight: 35.45 g / mol
- Molecular weight (Cl 2 ): 70.90 g / mol
- Density: 3,214 kg / m 3
- Electronegativity: 3.16
- Melting point: -102 ° C
- Boiling point: -34 ° C
Bromine is the only non-metal that is liquid at room temperature. It is the third of the halogens, and is slightly less reactive than chlorine. It is blood red in color, and gives off a reddish, pungent and toxic vapor, which must be handled with great caution. It constitutes a small percentage of the water in the oceans, from which it has mainly been extracted.
The properties of this element are:
- Atomic number: 35
- Atomic weight: 79.90 g / mol
- Molecular weight (Br 2 ): 159.80 g / mol
- Density: 3119 kg / m 3
- Electronegativity: 2.96
- Melting point: -7 ° C
- Boiling point: 59 ° C
Iodine (I)
Iodine is the penultimate of the halogens. It is a non-metal that occurs in a solid state, with a dark gray color. This element has the particularity that it sublimates , that is, it passes directly to the gaseous state. In other words, its solid evaporates . If a cold surface is put in the path of the steam, it will transform back into crystals.
Iodine is a very important element for human health, as it is part of the thyroxine molecule, which is the hormone of the thyroid gland. It is consumed through iodized salt, which contains a small percentage of sodium iodate NaIO 3 to cover the daily requirement for halogen. Thanks to iodine, conditions such as goiter are prevented.
The properties of this element are:
- Atomic number: 53
- Atomic weight: 126.90 g / mol
- Molecular weight (I 2 ): 253.8 g / mol
- Density: 4930 kg / m 3
- Electronegativity: 2.66
- Melting point: 114 ° C
- Boiling point: 184 ° C