What do some neon signs, party balloons, and few bulbs have in common? They all contain noble gases.
In this article, lets explore what are noble gases, where are they placed in the periodic table, some of the key properties of noble gases and their users.
At the end of the article, you can also find interesting noble gases worksheets that you can use for your classroom or at-home practice.
What are Noble Gases?
Noble gases are monatomic, odourless gases and have absolutely no reactivity towards any other element or compound.
Who Discovered Noble Gases?
In the year 1894, William Ramsay performed an interesting experiment. He was curious about the ‘Other Gases’ present in the air, apart from Oxygen and Nitrogen.
For the experiment, he segregated Oxygen first, followed by Nitrogen to isolate the ‘Other Gases’. Ramsay did this to study and understand their properties without any interruption from the remaining major gases.
On Separation, he found that indeed there is a gas present in very minute quantity. He later named that gas as ‘Argon’, meaning idle in Greek.
Hence, William Ramsay is credited as the first to discover Noble Gases.
Why Are They Called Noble Gases?
Nobility usually refers to something/someone who is unique and different from the expected qualities. These gases, which show entirely different behaviour compared to gases of other elements, are hence named ‘Noble Gases’.
They are also named so because of their immunity to any kind of influence from other elements, which is also a characteristic of ‘Noble’.
Where Are Noble Gases Found in Nature?
The primary source of Noble Gases in Earth’s atmosphere. These gases are obtained physically by processes like Liquefaction and Fractional Distillation.
Liquefaction is simply the conversion of the element’s gas state to a liquid state.
Fractional Distillation is more of a separating process than conversion. It separates the Noble Gases from the mixture of gases present in the air.
However, not all Noble Gases are obtained from air. For example, Helium and Radon, the topmost and bottommost elements of the Noble Gases Group, are not found in the air.
Helium is obtained from Natural Gas Wells. The gases emitted from these wells is filled with impurities. This then undergoes a purification process that results in pure Helium.
Radon, on the other hand, is a Radioactive element. Radon is always present in compound form. Pure Radon is a product of spontaneous radioactive decomposition. Spontaneous because the nuclei of Radon atoms decay by emitting energy and particles.
What Are the Colours of Noble Gases?
In their elemental stage, i.e., not in a combined state with other elements. Noble Gases are colourless. The first impression of being called the fancy name of being ‘Noble’ may give a false assumption of having colour.
Although this is the case, however, there are some instances where they ‘emit’ colour instead of ‘showing’ colour.
When valence electrons of Noble Gases are excited to a higher energy level than their present energy level, they absorb energy.
On dexcitation, they fall back to their original energy level, in the process of which they ‘emit’ energy.
This ‘emission’ of energy is what is referred to as them ‘showing’ colour. Otherwise, in their non-reactive, monoatomic stage, they do not have any colour.
These ‘emissions’ fall under the ‘Visible’ region of the colour spectra. This is because the wavelength and frequency of these emissions match the visible range, hence visible to our eyes.
The following are the colours of respective Noble Gases –
Helium (He) – Pink
Argon (Ar) – Red-Orange
Krypton (Kr) – Blue
Xenon (Xe) – Pale Green
Radon (Rn) – Pale Blue
Where Are Noble Gases in The Periodic Table?
The Periodic Table is a systematic arrangement of all elements that exist in the world. The orderly placing is essential to study and understand each of their characteristics.
The location of Noble Gases can be described as follows –
Position according to Group Number
Group refers to the vertical column in the Periodic Table, and there are 18 in it.
To better understand all the elements in the periodic table, the Groups are divided into ‘Group A’ and ‘Group B’.
Group A refers to the 1st, 2nd and then 13 through 18 groups, while Group B refers to groups 3rd to 12th. The former occupies the farthest left and farthest right, and the latter occupies the middle region.
The one on the farthest right of the Periodic Tables is the 8th vertical column or the 8th Group. This 8th Group is where all the Noble Gases are present.
Position according to Period Number
Period refers to the horizontal row in the Periodic Table, and they are a total of 7 in it.
At the end of each of the 7 periods, one Noble Gas is present. This implies that all 7 periods have at least 1 Noble Gas in them.
Combined Location
To name the location of a Noble Gas, the Group Number is followed by the Period Number.
For example, let us locate Xenon. So, Xenon is said to be in VIII A Group and 5th Period.
What Are the Elements Comprising the Noble Gases Family?
Noble Gases are 7. The 7th is the latest to be discovered a radioactive element, just like the one above it, Radon.
List of Noble Gases/Elements
The following is the Noble Gases list, in their increasing atomic number (mentioned in the brackets), down the group.
Helium (2)
Neon (10)
Argon (18)
Krypton (36)
Xenon (54)
Radon (86)
Oganesson (118)
What is the Electronic Configuration of Noble Gases?
- Definition: Electronic Configuration refers to the number of electrons present in an element.
The Electronic Configuration acts as a detailed composition of the number of electrons present in each of the inner and outer shells of the element.
To understand Electronic Configuration, you first need to understand the ‘Octet Rule’.
The Octet Rule refers to the presence of 8 electrons in the outermost shell of each element. Therefore, any element having the octet configuration is the most stable.
It so happens that all the elements of Noble Gases have a total of 8 electrons in their outermost shells, hence making them the most stable elements of the entire periodic table.
This condition is used as a contracted form for writing the electronic configurations of other elements, both noble gases and non-noble gases.
The following is the list of Noble Gases with their Electronic Configurations –
Helium (2) – 1s2
Neon (10) – [He] 2s2 2p6
Argon (18) – [Ne] 3s2 3p6
Krypton (36) – [Ar] 3d10 4s2 4p6
Xenon (54) – [Kr] 4d10 5s2 5p6
Radon (86) – [Xe] 4f14 5d10 6s2 6p6
Oganesson (118) – [Rn] 7s2 7p6 5f14 6d10
The following is the list of II A Group element, showing the example of how Noble Gases are used to write their Electronic Configurations –
Beryllium (4) – [He] 2s2
Magnesium (12) – [Ne] 3s2
Calcium (20) – [Ar] 4s2
Strontium (38) – [Kr] 5s2
Barium (56) – [Xe] 6s2
Radium (88) – [Rn] 7s2
What is the Valency of Noble Gases?
- Definition: Valency is simply the number of electrons in the outermost shell of an element.
There are 2 definitions of what Valency means regarding Noble Gases.
In one case, the number of electrons in the outermost shell of Noble Gases is 8, and so, 8 is considered the Valency of Noble Gases.
On the other hand, since the Noble Gases follow the rule concerning the Octet Rule, they are considered not to have any electrons that can act as ‘Valence electron’. Hence, this condition states the valency of Noble Gases as 0 and not 8.
General Characteristics of Noble Gases
One characteristic common to all Noble Gases is that they all have an outer electronic configuration as 8.
Also, they all are Colourless (in their ground-level state and not excited state) and Odourless.
They are always found as Mono atoms, meaning most of the time are constituted of 1 atom.
Properties of Noble Gases
Properties of Noble Gases give us an idea of how they react or not react in certain conditions and situations. For easy comprehension, these are divided into 2.
Physical Properties
- Definition: Physical Properties refer to the properties of Noble Gases where there are no structural changes or element/compound addition to the elements.
- What are the Boiling Points of Noble Gases?
- Boiling Point- Boiling Point refers to the temperature at which an element transforms from its liquid state to a gaseous state.
The nucleus of each element has an attraction towards each of the electrons that surround it. This attraction pulls the electrons towards themselves. This is also referred to as ‘Intermolecular forces of attraction’.
In Noble Gases, down the group, atomic radii increases. This is because one shell keeps on adding.
With the addition of each shell, the distance between the nuclei and the outermost electron increases, reducing the intermolecular forces of attraction.
Due to the above two phenomena of increase in atomic radii and decrease in intermolecular forces of attraction, Boiling Point increases down the group.
Therefore, at the top of the Group, the Boiling Point is the lowest and most negative, and at the bottom of the Group, the Boiling Point is the highest and least negative.
The following are the Noble Gases with their respective Boiling Points –
Helium: -272℃
Neon: -246℃
Argon: -186℃
Krypton: -152℃
Xenon: -107℃
Radon: -62℃
Oganesson: 177℃ (experimentally predicted)
- Why are Noble Gases Stable?
- Stability- Stability refers to the state of remaining unchanged.
Because the Noble Gases follow the Octet Rule and have 8 electrons in the outermost shell of their elements, they are the most stable of elements. Octet Rules equals Stability.
They are not interested in any element or compound near them or taken close to any element or compound. They are happy and stable where they are.
However, Stability decreases down the Noble Gases Group. This is because of an increase in atomic radii and a decrease in intermolecular forces of attraction.
Helium has the shortest atomic radius and the strongest intermolecular forces of attraction, hence most stable at the Group’s top.
Radon has the longest atomic radius and the weakest intermolecular forces of attraction, hence least stable at the Group’s bottom.
(Oganesson’s properties are still under study).
- What are the Ionization Energies of Noble Gases?
- Ionization Energy- Ionization Energy is the energy required to remove an electron from the outermost shell of an atom, to make the atom an ion.
Ions are charged atoms. They either possess a positive or a negative charge if they lose or gain an electron, respectively.
The number of electrons lost or gained is written along with the charge on the upper right corner of the element symbol.
The formation of ions is not easy in Noble Gases due to them being extremely stable.
Usually, atoms form ions to get closer to forming an octet configuration or to form an octet configuration directly. This is done by sharing electrons between the particles to form Covalent Bonds.
Covalent Bonds are formed to give stability, which is what each atom desires.
However, in Noble Gases, since they already possess 8 electrons in their outer shell, why would they want to lose or gain valence electron(s)?
For this to happen (which rarely occurs), the threshold energy required is very high to pull the valence electron(s) away from the intermolecular forces of attraction between the nucleus and the electron(s) and out of the outermost shell.
Therefore, Noble Gases have high Ionization Energies.
Period-wise, Noble Gases have the highest Ionization Energies in their respective periods. However, Group-wise, a decrease in the trend is shown.
As we move down the Noble Gases Group, the atomic radii increase, and the intermolecular forces decrease.
These two factors combine and make valence electron(s) exit from the bottom elements easier than the top elements.
Helium has the highest Ionization Energy, while Radon has the lowest Ionization Energy.
(Oganesson’s Stability still under study).
- Are Noble Gases Metals/Non-metals?
- Metallic Character- Metallic Character refers to the ease of the atom to lose valence electron(s).
In other words, this is also referred to as Electropositivity.
In the Noble Gases Group, as we move from top to bottom, an outer shell is observed with each period.
This addition increases the atomic radii and decreases the intermolecular forces of attraction between the nucleus and the valence electron(s).
Due to the above two factors, it becomes easier for the atom to lose valence electron(s) having no firm hold on them, thus giving it a positive charge(s)
Therefore, Metallic character increases down the group.
Helium is the least Metallic, while Radon is the most Metallic.
(Oganesson’s Metallic Character is still under study).
- Non-Metallic Character- Non-Metallic Character refers to the ease of the atom to gain valence electron(s).
In other words, this is also referred to as Electronegativity.
In the Noble Gases Group, as we move from top to bottom, an outer shell is observed with each period.
This addition increases the atomic radii and decreases the intermolecular forces of attraction between the nucleus and the valence electron(s).
Due to the above two factors, it becomes harder for the atom to gain any more valence electron(s) having no firm hold on them, thus not giving it a negative charge(s)
Therefore, the Non-Metallic character decreases down the group.
Helium is the most Non-Metallic, while Radon is the least Non-Metallic.
(Oganesson’s Non-Metal Character is still under study).
- How is the Reactivity of Noble Gases?
- Reactivity- Reactivity refers to a reaction or non-reaction to specific changes in conditions of an atom.
The reactivity of Noble Gases is dependent on Stability and Ionization Energy.
Noble Gases are the most stable of compounds with very high Ionization Energies. However, for any reactivity to occur, a large amount of work needs to be done, which is highly undesirable.
Therefore, Noble Gases are highly Unreactive/Non-reactive elements. However, they can be made to react if certain favourable conditions are created.
- Why are Noble Gases Inert?
- Inertness- Inertness refers to the ability to be non-reactive and maintain stability.
The inertness of Noble Gases is dependent on Stability and Ionization Energy.
Noble Gases are the most inert of compounds with very high Ionization Energies. For the inertness to be removed, a lot of work needs to be done, which is highly undesirable.
Therefore, Noble Gases rarely form bonds with other atoms. However, they can be made to lose their inertness if certain favourable conditions are created.
- What are the Charges of Noble Gases?
- Charge- Charge refers to the valence electron(s) lost or gained on reaction with an element of the same species or different with another compound.
When an element is said to have charge(s), it can no longer be called an atom but should be called an ion, irrespective of whether that charge is positive or negative.
Charge Formation is the ability of an atom to carry out the loss or gain of electron(s). This is influenced by Stability and Ionization Energies.
For Noble Gases to undergo charge formation, a large amount of work needs to be done, which is highly undesirable.
As we move down the group, Electropositivity/Metallic Character increases. This increases the bottom elements’ chances of losing valence electron(s) and gaining positive charge(s).
On the other hand, Electronegativity/Non-Metallic Character decreases. This decreases the bottom elements’ chances of gaining valence electron(s) and gaining negative charge(s).
- Do Noble Gases Conduct Electricity?
- Conduction of Electricity- Conduction of Electricity refers to the ability of an element to allow passage of current through it.
The current is a flow of charges from one point to another point, and these charges are electrons. So the electron flow is what induces the conduction of electricity.
In Noble Gases, due to their high Stability, high Ionization Energies and low Charge Formation Capacity, they are very bad conductors of electricity or rather excellent insulators.
However, as in Colour production, if electrons are excited from ground state/lower energy level to higher energy level, Noble Gases can conduct electricity.
Since electricity is a flow of charges, if a Noble Gas Element is first made to lose or gain electron(s), they become charges, then allowed for exciting and moving to higher energy levels, though not very good quality Noble Gases can conduct electricity.
In Noble Gases Group, as we move down the group, the Charge Forming capacity (mostly positive) increases.
Therefore, elements at the bottom are much more suitable for the conduction of electricity than the top elements of the Group.
Although this is the case, the rare examples of Noble Gases conducting electricity are recorded by Neon and Argon.
(Oganesson’s Conduction of Electricity is still under study).
Chemical Properties
- Definition: Chemical Properties refer to the properties of Noble Gases where there are structural changes or element/compound addition to the elements.
- Do Noble Gases Form Compounds?
- Compound Formation- Compound Formation is the ability of element(s)/atom(s), to combine with other element(s)/atoms(s) to form compounds.
These compounds have much better physical and chemical properties than their individual properties and have a much more comprehensive range of uses and applications.
The Compound Formation ability of Noble Gases depends on Stability, Ionization Energies and Charge Formation. The first two are high, and the third is low (except in some).
Therefore, it is challenging to form compounds of Noble Gases.
Some of the rare examples of Compound Formation seen in Noble Gases are –
Covalent Compounds:
Helium – Na2He
Krypton – KrF2, Kr(OTeF5)2
Xenon – XeF2, XeO3, XeOF4
Radon – RnF2, RnO3
Ionic Compounds:
Neon – (NeAr)+, (NeH)+
Argon – ArH+
(Oganesson’s Compound Formation is still under study).
- Are Noble Gases Flammable?
- Flammability- Flammability is the ability of an Element/Compound to catch fire/burn.
An element/compound, when exposed to air, the oxygen present in the air reacts with the said element and catches fire. Therefore, reactivity is a crucial factor in being classified as flammable/non-flammable.
Noble Gases are Stable and Inert. Hence, they do not react with air when exposed to it.
Therefore, all Noble Gases are Non-Flammable.
What are the Interesting Facts about Noble Gases?
Noble Gases are very peculiar in their properties. This peculiarity gives them the ability to have Interesting Facts.
Some of the Interesting Facts are mentioned below –
- Helium has the lowest Melting and Boiling Points of all the elements in the entire Periodic Table.
- Though Helium has 2 valence electrons and not the usual Octet-8 electrons, it is still considered a Noble Gas.
This is because Noble Gases all have a stable and complete configuration among all their elements. So, for example, though Helium has 2 electrons, it is one of the most stable elements.
Also, it has 2 energy levels. Out of which, the second is an s-energy level. The s-energy level has the capacity of 2 electrons and not more than that.
So, even if Helium wanted to take in more electrons to gain the octet configuration, it will not be possible. However, Helium does fulfil the requirement of filling the s-energy level and forming a ‘Duplet’ instead of the usual ‘Octet’.
- The name ‘Krypton’ comes from the root word of ‘Kryptos’ in Greek, which means “the hidden one”.
- The name ‘Xenon’ comes from ‘Xenos’ in Greek which means “stranger/foreigner”.
- All Noble Gases except Radon have Isotopes (compounds having the same atomic number but different atomic mass).
What are the Uses/Practical Applications of Noble Gases?
Though Noble Gases are highly Stable, Metallic, Inert, Non-flammable; have high Ionization Energies, low Reactivity, low Charge Formation, low Compound Formation; do not Conduct Electricity, they still have vast Uses and Practical Applications.
The following list can note the Importance of Noble Gases –
Helium
- Helium is lighter in density than air. This gives it the ability to float in the air and rise above the atmosphere.
This property of Helium is used to fill balloons of all sizes, whether small party balloons or large airships and blimps.
The light-weighted Helium keeps the balloons afloat and does not let them sink.
Neon
- You might have heard about ‘Neon Lights’. These Neon Lights is where Neon is used in eye-catching billboards due to its emission of bright light.
Argon
- Argon is used in Light Bulbs. Here, Argon is a substitute for Air.
Since air reacts with the Tungsten material (another element from the Periodic Table), light bulbs needed a non-reactive gas.
Hence, Argon is chosen because of its inertness.
Krypton
- Krypton is used in specific Lasers.
- In Headlamps, Krypton is used.
- It is also used in Flat Panel Display.
- Another use of Krypton is as a filler in Double Glazing.
Double glazing is a type of glass setting, where two glass panels are filled with a gas between them. This is done to reduce the amount of incoming heat.
This filling gas is where Krypton is used due to its property of Low Thermal Conductivity (low heat transmission).
If natural air is used as a filler, it will not lower the heat transmission due to its high thermal conductivity.
Xenon
- Krypton is used in specific Lasers.
- It is also used in Flat Panel Display.
- Since the early 90s, Xenon is being used in Vehicle Headlights to improve road safety; this is because Xenon emits bright lights that enhance contrast and colour visions.
- In Medicine, Xenon is used as a natural anaesthetic. It makes the inhaler fall unconscious for a certain period so that the doctor can operate on them.
The heart rate and blood pressure are better monitored on the administration of Xenon as the sedative.
- In Satellites, Xenon is used as a Propeller that steers the movement of the satellite. This is because Xenon is lighter in weight and hence can be manoeuvred easily.
Radon
- For the treatment of cancer, a procedure called Radiotherapy is used. The Radio in the Therapy because of the use of a radioactive element.
Radon is used as that radioactive element.
(Oganesson’s uses/applications are still under study)
Noble Gases Worksheets
Halogens and Noble Gases Anagrams – worksheet
Noble Gases – Word Search Activity Worksheet
Properties of Noble Gases worksheet
Noble Gases Properties – Memory / Flash Card for Students
Noble Gases Electron Configuration Worksheet
Noble Gases have genuinely proven their name of having special and distinctive characteristics. Consequently, their applications and uses cannot be substituted with other elements of the periodic table.
There is speculation that there are still Noble Gases yet to be discovered. What wonder would they bring to the world? Let’s wait and watch.
