Nomenclature and Identity
Noble gas names: The elements in Group 18 are commonly called noble gases because they do not easily react with other substances. They are also called inert gases because they tend to stay unchanged in chemical reactions due to their stable atomic structure.
Element list: This group includes six well-known elements—helium (He), neon (Ne), argon (Ar), krypton (Kr), xenon (Xe), and radon (Rn). Each of these is a gas at room temperature and shares similar properties.
Oganesson’s position: Oganesson (Og) is a very heavy element placed in the 7th period of the periodic table. Although it is different in some ways, scientists have grouped it into Group 18 because of its expected similar outer electron arrangement.
Atomic Nature
Monoatomic form: Unlike many other elements that form molecules, noble gases are found as single atoms in nature. This means they don’t join with other atoms because they are already stable.
Gaseous state: All noble gases naturally exist as gases when kept at room temperature. You won’t find them as solids or liquids under normal everyday conditions.
Electronic Configuration
Full outer shells: One reason noble gases are so stable is that they have full outer shells of electrons. This means their atoms don’t need to gain or lose electrons to become stable, unlike other elements.
Helium’s duplet: Helium is a special case among the noble gases. It only has two electrons, but that’s enough to fill its only energy level. This makes helium very stable, even with just two electrons.
Octet stability: All other noble gases have eight electrons in their outermost energy level. This “octet” of electrons makes their atoms balanced and non-reactive.
Chemical Reactivity
Unreactive nature: Noble gases are known for being chemically unreactive. This means they almost never take part in chemical reactions with other elements because their electron shells are already full.
No bond formation: Unlike other elements that need to gain, lose, or share electrons to form chemical bonds, noble gases usually don’t form bonds. They are already stable by themselves.
No common reactions: Under normal conditions like room temperature and regular pressure, noble gases do not combine with other elements to form new substances.
Physical Properties
Colorless and odorless: You cannot see or smell noble gases because they are colorless and odorless. This makes them invisible in the air around us.
Low melting and boiling points: Noble gases turn into liquids or solids only at very low temperatures. This is why they remain gases in most situations we experience every day.
Trend down the group: As you go from helium to radon in Group 18, the atoms get larger and heavier. This causes their melting and boiling points to increase gradually.
Poor conductivity: Noble gases do not allow heat or electricity to flow through them easily. That’s why they are not used as conductors in electrical circuits.
Atomic Size
Increasing size: As we move down the group from top to bottom, each noble gas has more electron shells than the one above it. This makes the atoms larger in size.
Uses of Group 18 Elements
Helium uses: Helium is used to fill balloons because it’s lighter than air. It’s also used to cool powerful magnets and in machines that need very low temperatures, like in cryogenics.
Neon uses: Neon lights up signs in bright colors when electricity passes through it. It’s also used in some types of lasers.
Argon uses: Argon gas is often used to protect things during welding because it doesn’t react with hot metals. It’s also used in some types of light bulbs and in making titanium.
Krypton uses: Krypton is used in high-intensity lights, like those used in airports, and in lasers for medical treatments.
Xenon uses: Xenon is used in flash lamps for cameras and in lasers for eye surgery and other special uses.
Radon uses: Radon is a radioactive gas. In controlled amounts, it’s used in medicine to help treat certain types of cancer.
Occurrence
Atmospheric presence: Small amounts of noble gases can be found naturally in the air we breathe. They are not very common, but they are always present in tiny amounts.
Radon source: Radon comes from rocks and soil where radioactive elements slowly break down. It can move into the air or even inside buildings through cracks in the ground.