Question

How would you justify the inclusion of group 18 in between group 17 and group 1 in the periodic table?

Answer 1

1. Noble gases were discovered later, after Mendeleev’s periodic table was made, so their place was not originally fixed.
2. They form a new group called group 18 (formerly the zero group).
3. Noble gases have stable closed-shell electronic configurations (helium: 1s²; others: ns²np⁶).
4. They are chemically inert under ordinary conditions, showing neither electropositive nor electronegative nature.
5. Group 17 elements (halogens) are the most electronegative, while group 1 elements (alkali metals) are the most electropositive.
6. Placing noble gases in between group 17 and group 1 logically reflects their neutral chemical nature.
7. This arrangement follows IUPAC conventions and reflects their unique non-reactive properties.