Chemical Properties of Group 18 Elements: Introduction, Properties and Uses

A chemical property describes a substance’s ability to undergo a specific chemical change. However, unlike physical properties, chemical properties can only be observed while the substance is being transformed into another substance.

The elements in the \({\text{s}}\) and \({\text{p}}\) blocks of the periodic table are known as representative elements or main group elements. Elements in groups \(1\) and \(2\) are classified as \({\text{s}}\)-block elements, while elements in groups \(13\) to \(18\) are classified as \({\text{p}}\)-block elements.

In this article, we will learn about the chemical properties and uses of group \(18\) or Noble Gases, a group in the \({\text{p}}\)-block.

Group 18 Elements: Noble Gases

Group \(18\) is placed on the extreme right in the periodic table. There are six elements that include Helium \(\left({{\text{He}}} \right),\) Neon \(\left({{\text{Ne}}} \right),\) Argon \(\left({{\text{Ar}}} \right),\) Krypton \(\left({{\text{Kr}}} \right),\) Xenon \(\left({{\text{Xe}}} \right),\) and Radon \(\left({{\text{Rn}}} \right).\) These elements are commonly known as noble gases or inert gases as these elements are chemically inert and do not take part in any reaction.

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Occurrence of Group 18 Elements

Noble gases are always found in their state due to their inert nature. Except for Radon, all of these gases are atomically present in the atmosphere. Their total percentage in dry air is about \({\rm{1\% }}\) by volume, with Argon \(\left({0.93\% } \right)\) constituting the majority. It is emitted into the atmosphere primarily as a result of the electron capture of potassium.

Helium is also present in natural gas in amounts ranging from \(2\) to \(7\% .\) Helium and neon are found in trace amounts in radioactive element minerals such as monazite, Clevite, pitchblende, and others. Certain springs’ water contains Helium, Neon, and Argon.

Radon is radioactive and does not exist in its form because it decays so quickly.

Electronic Configuration of Group 18 Elements

Except for Helium, all noble gas atoms have eight electrons in the valence shell. The general electronic configuration of noble gases (with the exception of \({\text{He}}\)) is \({\text{n}}{{\text{s}}^2}{\text{n}}{{\text{p}}^6}.\) Helium has an electronic configuration of \(1{{\text{s}}^2}.\)

Because these configurations are stable, the noble gases have no tendency to gain or lose electrons and thus do not participate in chemical reactions.

Existence of Group 18 Elements

Noble gases are all monoatomic, colourless, and odourless gases. The monoatomic state of these gases is caused by the atoms’ stable electronic configuration. As a result, they are incapable of even combining with one another.

Chemical Properties of Group 18 Elements

Noble gases are not very reactive. Their inertness to chemical reactivity is attributed due to the following reasons:

• i. Because of their stable electronic configuration, these elements are chemically latent.
• ii. Elements in Group \(18\) have a high positive electron gain enthalpy and a high ionisation enthalpy.
• iii. Neil Bartlett predicted in \(1962\) that Xenon would react with platinum hexafluoride. He was the first to develop a xenon compound known as xenon hexafluoroplatinate \(\left({\text{V}} \right).\) Later, many xenon compounds, such as fluorides, oxyfluorides, and oxides, were added.
• \(\underset{{{\text{Xenon}}}}{\mathop {{\text{Xe}}}} + \underset{{{\text{Platinum}}\,{\text{Hexafluoride}}}}{\mathop {{\text{Pt}}{{\text{F}}_6}}} \to \underset{{{\text{Xenon}}\,{\text{Hexafluoroplatinate}}\left({\text{V}} \right)}}{\mathop {{\text{Xe}}\left[{{\text{Pt}}{{\text{F}}_6}} \right]}} \)
• iv. The chemical reactivity of group eighteen elements increases as the ionisation enthalpy decreases as one moves down the group.
• v. Helium, Argon, and neon have too high ionisation enthalpies to shape compounds.
• vi. Because Krypton’s ionisation enthalpy is marginally higher than that of Xenon, it can only form krypton difluoride.
• vii. Although Radon has a lower ionisation enthalpy than Xenon, it only forms a few compounds, such as radon difluoride and a few complexes, because it has no stable isotopes. In any case, Xenon shapes a proportionately large number of compounds.

Preparation and Properties of Some Compounds

• 1. When \({\text{Xe}}{{\text{F}}_6}\) is partially hydrolyzed, it produces oxyfluoride, \({\text{XeO}}{{\text{F}}_4}\) and \({\text{Xe}}{{\text{O}}_2}{{\text{F}}_2}.\)
• 2. \({\text{Xe}}{{\text{F}}_2},{\text{Xe}}{{\text{F}}_4},\) and \({\text{Xe}}{{\text{F}}_6}\) They are extremely effective fluorinating agents.
• 3. \({\text{Xe}}{{\text{F}}_6}\) is a highly reactive compound. It cannot be stored in glass or quartz containers because it readily reacts with the \({\text{Si}}{{\text{O}}_2}\) present in the glass.
• 4. \({\text{Xe}}{{\text{O}}_3}\) is a colourless, explosive solid with a pyramidal structure. \({\text{XeO}}{{\text{F}}_4}\) is a colourless, volatile liquid with the shape of a square pyramid.
• 5. \({\text{Xe}}{{\text{F}}_2}\) is a linear material, whereas \({\text{Xe}}{{\text{F}}_4}\) is a square planar compound. The shape of \({\text{Xe}}{{\text{F}}_6}\) is distorted octahedral.

Uses of Group 18 Elements

The uses of Group 18 elements are discussed below:

Helium Uses

• i. Helium is used in the filling of air balloons and aircraft. This is due to the fact that it is flammable and has a very low density. We use fluid Helium as a cryogenic agent to perform tests at extremely low temperatures because it has a very low boiling point of only \(4.2\,{\text{k}}.\)
• ii. Liquid Helium is commonly used in the cryoscopy process required for superconductivity. Fluid helium is frequently used to cool superconducting magnets in atomic magnetic resonance spectrometers.
• iii. It is also used as a cooling gas in gas-cooled atomic reactors as well as a stream gas in gas-fluid chromatography.
• iv. It is also an important component of the oxygen cylinders used in deep-sea diving.

Neon Uses

• i. Neon lights in reddish-orange hues are used to create advertising signs. It is also used in these types of lights when many other gases are required to produce lights of various colours.
• ii. Neon can also be found in lightning arrestors, high-voltage indicators, television tubes, and metre tubes.
• iii. Neon and Helium are used to create gas lasers.
• iv. In many types of gas-filled electron tubes, neon is used singly or in mixtures with other gases in the electronics industry.
• v. Because Helium is less soluble in blood than nitrogen at high pressure, marine divers use a mixture of Helium and neon with oxygen for breathing in the sea.

Argon Uses

• i. Argon is used in incandescent light bulbs to prevent the filament from oxidising too quickly. This extends the bulb’s life.
• ii. Argon is widely used in the welding and casting industries, particularly in the production of speciality alloys and titanium. During arc welding, it is also used as a shielding gas.
• iii. Argon can be used as a carrier gas in filmmaking.
• iv. It provides a blanket atmosphere for crystal growth (and, for example, in viniculture). This noble gas is also used in cryosurgery, refrigeration, fire extinguishing, spectroscopy, and airbag inflation.
• v. Argon is frequently used as a liquid target for neutrino experiments and direct searches for dark matter.

Krypton Uses

• i. It is used in a variety of electric and fluorescent lamps, as well as in a flashlamp used in high-speed photography.
• ii. They could even react with fluorine, which is a highly reactive gas.

Xenon Uses

• i. It is used in Xenon flash lamps, which are flash lamps.
• ii. It’s also used in stroboscopic lights and photographic flashes.
• iii. Lasers are created with the assistance of \({\text{Xe}}\) gas.
• iv. The element \({\text{Xe}}\) is a natural anaesthetic.
• v. Inhaling a mixture of oxygen and Xenon produces a hormone that aids in the production of Red Blood Cells (RBCs).
• vi. It is used to measure blood flow and to image the brain, heart, and lungs.
• vii. The element is also used in NMR spectroscopy.

Summary

Group \(18\) is placed on the extreme right in the periodic table. There are six elements that include Helium \(\left({{\text{He}}} \right),\) Neon \(\left({{\text{Ne}}} \right),\) Argon \(\left({{\text{Ar}}} \right),\) Krypton \(\left({{\text{Kr}}} \right),\) Xenon \(\left({{\text{Xe}}} \right),\) and Radon \(\left({{\text{Rn}}} \right).\) Group \(18\) elements are called Noble gases, and they are chemically inert as they have a stable electronic configuration. These elements have high ionization enthalpy and higher positive electron gain enthalpy. In this article we also learned the uses of each element of Group \(18.\)

FAQs on Chemical Properties of Group 18 Elements

Q.1. What is the name and chemical properties of the elements in Group 18?
Ans: The name of Group \(18\) elements is Noble Gases. These elements are not very reactive. Their inertness to chemical reactivity is attributed due to the following reasons:
i. Because of their stable electronic configuration, these elements are chemically latent.
ii. Elements in Group \(18\) have a high ionisation enthalpy.
iii. The electron gain enthalpy of this group is zero.

Q.2. Do Group 18 elements react with other chemicals?
Ans: In general, noble gases are chemically inert. This is because they already have the desired \({\text{s}}\) and \({\text{p}}\) electrons in their outermost (highest) energy level, so they do not react with other elements.

Q.3. Are group 18 elements chemically inert?
Ans: Yes, this is because group-\(18\) elements have completely filled \({\text{s}}\) and \({\text{p}}\) orbitals. They are more stable and have the least reactivity. As a result, group-\(18\) elements are referred to as inert gases.

Q.4. Does the hydrolysis of \({\text{Xe}}{{\text{F}}_6}\) lead to a redox reaction?
Ans: No, the products of hydrolysis are \({\text{XeO}}{{\text{F}}_4}\) and \({\text{Xe}}{{\text{O}}_2}{{\text{F}}_2}\) where the oxidation states of all the elements remain the same as it was in the reacting state.

Q.5. Why has it been difficult to study the chemistry of Radon?
Ans: It is difficult to study the chemistry of Radon because it is a radioactive substance having a half-life of only \(3.82\) days.

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