What is Noble Gases?
Do you know it's helium gas that is filled in the balloons we used to play with? Helium is a noble gas but its properties are quite different from the properties of other noble gases. Group 18 elements consist of the noble gases which were not known at the time of Mendeleev and so were not added to the Mendeleev's periodic table but later after the discovery of helium and argon in the periodic table Ramsay in 1896 suggested a new group for such noble gases.
The new group formed was known as the zero group having 6 electrons in it. These elements came to be known as noble gases, inert gases, the zero group elements or the group 18 elements.
Noble gases are odorless, colourless, monatomic gases. They are referred to as noble gases as they are quite unreactive except under some extreme conditions. Their inertness results from their completely filled valence shell. So let's get started with the characteristics of group 18 elements.
General Characteristics Of Noble Gases
Group 18 elements are known as noble or inert gases. They are called inert because they do not take part in any chemical reaction except under some extreme conditions and so we can say that they are chemically inert.
All the elements of group 18 i.e. Helium (He), Neon(Ne), Argon(Ar), Krypton(Kr), Xenon(Xe), Radon(Rn), Organesson(Og) are non-metallic elements.
The zero group is designated so because of the zero valence electrons that the elements of this group have.
Group 18 is placed in the extreme right-hand side of the long periodic table. This position is justified with the fact that each column from left to right proceeds with the addition of one valence electron in its outer shell until it gets completely filled in Group 18.
Their nature of reactivity is almost inert and serves as an intermediate bridge between the strong electronegative elements of VIIA and strong electropositive elements of IA groups in the periodic table.
All the members of the 18th group possess 8 electrons in their outermost shell except for Helium which has 2 electrons in its outermost shell.
Electronic Configuration of Zero Group Elements
Zero Group Elements | Electronic Configuration |
He | ...1s2 |
Ne | ...2s2, 2p6 |
Ar | ...3s2, 3p6 |
Kr | ...3d10, 4s2, 4p6 |
Xe | ...4d10, 5s2, 5p6 |
Rn | ...4f14, 5d10, 6s2, 6p6 |
Og | ...5f14, 6d10, 7s2, 7p6 |
Characteristics of Noble Gases
All the gases except for helium possess ns2, np6 configuration and hence the differentiating electron enters into p-subshell and thus, they are included in p-block elements.
All the noble gases except helium which has 1s2 configuration, a completely filled 1st shell have their outermost shell with a complete octet.
Their outer shell configuration is:
He: 1s2
Rest all: ns2 np6
These elements also called noble gases have no tendency to lose or gain electrons because of a completely filled outer shell or stable configuration and so usually under normal conditions do not participate in chemical reactions.
All the elements of group 18 are gases and Rn and Og are radioactive ones. These gases are also called rare gases because of their presence in very minute quantities in the atmosphere.
These gases are almost inert because of no availability of valence electrons. However, under extreme conditions, some compounds of xenon and two krypton fluorides have been synthesized.
All of them are colorless, odorless, monoatomic gases.
Conclusion
If you are keen to learn more about Group 18 Elements Characteristics, do check out the Vedantu website. You can use the information for preparing about the subject.
FAQs on Group 18 Elements Characteristics
1. Why are Group 18 Elements low reactive?
Reactivity of an element depends upon the presence of its electrons in the outermost valence shell. The element always has a tendency to complete its valence shell either by taking or giving valence electrons thereby attaining a stable state. However, the group 18 elements already have a completely filled-up valence shell. Hence they have no tendency to react further and disrupt their stability and prefer to remain in the inert state. That is why they are often referred to as noble or inert gases. Hence they remain non-reactive or very low reactive under some extreme conditions. At Vedantu website students can find all information about Group 18 Elements and characteristics.
2. Write some uses of Noble Gases.
In spite of the inert nature of the noble gases, they have been used in many places mainly in industries depending upon their inert character.
Helium is used as a cryogenic agent, in balloons, and in certain industries.
Neon gas can ionize under high voltage and this property has been used in fluorescent bulbs and in various release tubes. When Neon is energized using high voltage it emits red lights making the bulbs shine in a reddish-orange manner.
Argon is used as an inert atmosphere for many chemical reactions performed in chemical laboratories and research hubs. It is also used in various metallurgical industries.
Radon is a radioactive gas that occurs naturally. The radioactive nature of the gas is used in cancer treatment as radiotherapy.
Krypton is often used in fiber lights and release tubes.
3. What are the physical characteristics of Noble gases?
The physical characteristics of Noble Gases can be listed as follows:
These gases are colourless, tasteless, and odourless.
The only force that exists in inert gases is the Van der Waals force. The force is weak in Helium and increases down the group with the increasing polarity capacity of the molecules with an increase in radii of the elements.
They have a stable nature and so in a free state, these are monatomic gases.
The weak Van der Waals forces cause low melting and boiling point of these gases. However these increase down the group with increasing van der waals forces.
With the increasing size of the atom, there is an increase in liquefaction of the gases down the group.
These are slightly soluble in water. From He to Rn solubility increases.
In a specific period, the atomic radii and the ionization enthalpy of the noble gases are the largest.
Electron gain enthalpy follows the trend Ne>Ar=Kr>Xe>Rn>He
4. Write the uses of Helium.
Most of the inert gases are still not in random use except for helium which is used in the industrial markets and chemical uses. The uses of Helium are given below:
Oxygen cylinders used underwater for proper breathing have helium as its major component.
In gas-cooled atomic reactors, the cooling gas used is Helium.
In gas-fluid chromatography, Helium is used as the streaming gas.
In Cryoscopy helium is used for the superconductivity.
Air balloons are filled with helium. It is also used in aircraft because it has a very low density and is flammable.
In chemical labs and industries often helium is used as the cryogenic agent to perform certain chemical reactions which need extreme low temperatures.
5. Why do noble gases glow and in what colour?
Noble gases are usually very non-reactive because of their complete outer shell and stability arising out of that. They do not have any tendency to gain or lose electrons and disturb the stability. However, under high voltage electric discharge their electrons get excited and they jump from a lower stable state to a higher energy state, and during this leap they emit light. Noble gases glow when high voltage is applied to them by the electrodes. Helium glows in pink color, neon in reddish-orange, krypton in yellow-green, xenon in lavender blue, and argon glows in light blue colour.
6. Group 18 Elements are Reactive? Why?
The group 18 elements are called noble or inert gases. As the name suggests these are inert because chemically they are very less reactive or not at all reactive.
This is so because they have a stable electronic configuration which means they have no tendency to lose or gain electrons because of completely filled outer shell. The full valence electron shells of these atoms make the noble gases extremely stable. These are extremely non-reactive. Usually, under normal circumstances, they do not react or take part in any chemical reactions however there exist some exceptions.
7. Give Some Uses of Noble Gases
The below mentioned are some prominent uses of the group 18 elements or the noble gases.
Neon is used in fluorescent bulbs, it is also used in various release tubes. The reddish-orangish shine to these bulbs is given by the neon itself.
Argon is used in various metallurgical processes. Also gives a stable atmosphere in research centers.
Radon can be used in the treatment of cancer.
Krypton is used in fiber lights also in release tubes.