[Chemistry Class Notes] Group 18 Elements Characteristics Pdf for Exam

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

 

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.

Conclusion

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