Noble Gases – Group 18 elements

What are Noble Gases?

Noble Gases in the Periodic Table are a group of seven chemical elements, all of which are found under group 18 in the Periodic Table. As their name suggests, Noble Gas elements are monatomic gases under standard conditions and they all have similar physical and chemical characteristics. The Nobel Gases are the following seven Periodic elements: Helium (He), Neon (Ne), Argon (Ar), Krypton (Kr), Xenon (Xe), Radon (Rn), and Uninoctium (Uuo), which is among the newest elements in the Periodic Table. It was recognized and classified as a Noble Gas back in December 2015.


Physical Characteristics of the Noble Gases

Noble Gases have similar physical characteristics. These elements are colorless and odorless, and they occur in a gaseous state at standard conditions. Noble Gases are monatomic elements – that means that they exist as single atoms. Their melting points and boiling points are significantly low and they are quite close to each other. Noble Gases have a full outer shell made out of valence electrons. Their density is relatively low – a group trend, which all Noble Gases share. As their atomic numbers increase in the Periodic Table, these elements’ enthalpy of vaporization increases from 0.08 (for Helium) up to 18.1 (for Radon).Their atomic radius also increases as their atomic numbers progress further.



Chemical Properties of the Noble Gases

Noble Gases are considered to be highly unreactive elements, unless they have been exposed to extreme conditions. These elements are usually non-flammable and they are atomically stable. Thus, they do not form chemical bonds and lack the other elements’ tendency of gaining or losing electrons. Due to the extremely low chemical reactivity of Noble Gases there are only several hundred compounds of Noble Gases found up to date.


Bonding and reaction to other elements and compounds

Because of the extremely low reactivity of Noble Gas elements, their by-products aren’t as variable as the ones formed by bonds and compounds of other chemical elements in the Period Table. Heavier Noble Gas elements, like Xenon and Krypton, can form compounds with Oxygen. Xenon is the only Noble Gas to have a large variety of compounds, as it reacts highly with Fluorine. Radon is highly radioactive and it forms radon isotopes. Noble Gases do not react when exposed to water and their solubility in water is quite low.


Uses and applications of Noble Gases

Due to the low boiling points and melting points in Noble Gas elements they have a large application in magnet manufacturing, in refrigerants, in breathing gases, in lighting installations, and even in medicine.


Argon, Neon, and Xeon have a large application in incandescent light bulbs, in neon signs, in lasers, in halogen lamps, and so forth. The gas discharge emission of Noble Gases produces various colors in a wide specter, which makes them useful in colorful lighting installations. These elements are used in medicine for eye surgery lasers, for microfabrication, and for asthma medicine. Helium has a large application in airships, balloons and underwater breathing supplies. Argon is useful in metallurgy as a shield for welding arcs, and it’s also useful in the production of silicon.


Noble Gases on Earth

Noble Gas elements are found all over the Earth’s crust, in the Earth’s atmosphere and in the visible part of the Universe. Helium is extremely abundant in the Solar System as it has an abundance of 2343ppm. On the other hand, Argon is the most abundant Noble Gas in the Periodic Table, as it has the highest volume fraction in particles per million in the Earth’s atmosphere. Helium, Neon and Argon are also found in igneous rock masses on the Earth’s crust. Most Noble Gasses can be derived or extracted from air and other gases.