Noble gas characteristics
Noble gases are defined by the following characteristics:
- They have all the electrons corresponding to their last shell. Helium has 2 and the others have 8, which completes its octet rule.
- Due to the above, they are monatomic elements , that is, they are naturally found as individual atoms, and not combined with other elements.
- They have great stability in extreme conditions. For example, helium is one of the main components of the sun, hence its name from Greek etymology: helios, sun .
- They show little reactivity . They are generally incapable of forming bonds with other elements, which is why they are classified as inert or non-reacting gases .
They are fluorescent substances . When they are excited by the influence of electrical charges, they give off a luminescence (light) of particular colors, which vary depending on the noble gas in question.
All noble gases are
The helium has an atomic number of 2 and is, together with hydrogen, the element most abundant in the universe ; it forms the stars and other celestial bodies. It is the second lightest element and has an atomic mass of 4.0026 g / mol. It is odorless and colorless and does not react, so it is difficult for it to participate in a chemical reaction.
Due to its low weight, it is used to fill metallic balloons for parties and airships . Thus, these float for a long time to achieve their purpose. A curious fact is that through it sound travels faster than in air. Therefore, when a little of this noble gas is breathed in, the voice is altered and becomes higher.
The Neon has an atomic number of 10 and an atomic weight of 20 179 g / mol. It is an odorless, colorless and tasteless gas and has a wide application in the manufacture of fluorescent lamps. These are better known as neon lamps, as is, and they stand out for the amount of light they emit, of different colors, when an electric current is introduced.
They are placed outside commercial establishments and fulfill the objective of attracting attention. Neon is also used to create devices such as televisions and billboards.
The argon having an atomic number of 18 and is the third noble gas. It is also odorless, colorless and tasteless, and is the most widely used in the industry as an insulator. In addition, in the bottled beverage industry , a charge of argon is added so that it displaces the air in the container and there is not so much oxygen that it causes a rapid decomposition of the product.
This procedure also applies during vacuum packing of some foods. A stream of argon (or nitrogen, also inert, in other cases) replaces the air inside the package and finally suction is applied to close the package and ensure a much better preservation of the food. Argon is also used in fluorescent lamps and lasers .
Krypton has an atomic number of 32 and an atomic mass of 83,798 g / mol. It is an odorless, colorless and tasteless gas. Since the electrons in its last shell are further from the nucleus than in the previous gases, they are less attracted. This gives it a certain degree of reactivity, and therefore it has been possible to find chemical compounds of krypton .
This gas can combine with highly electronegative elements such as fluorine (F) and oxygen (O). Krypton has 6 stable isotopes and 17 radioactive isotopes are known to it. That is why, from this element, it is convenient to handle noble gases in the laboratory, with great care and with personal protective equipment.
Xenon has an atomic number of 54 and an atomic mass of 131,293 g / mol. It is odorless and colorless and one of the heaviest noble gases in the entire periodic table. In medicine it is used as an anesthetic , and in the automotive industry it is a raw material for the manufacture of powerful headlights , thanks to its high fluorescent capacity.
Radon has an atomic number of 86 and an atomic mass of about 222 g / mol. It is a highly radioactive element and is part of the radioactive decay chain of uranium-238 . After emitting its radiation, it is converted into other elements with a lower atomic mass. Contact with this element is very dangerous and occurs in the combustion of cigarettes, being one of the main cancer-causing agents.