NEETChemistryClassification of Elements and Periodicity in Properties
Why is helium positioned in the p-block of the Periodic Table?
Options
- ABecause it has a completely filled valence shell
- BBecause it has a high atomic number
- CBecause it belongs to the alkali metals
- DBecause it has a half-filled valence shell
Correct answer
A. Because it has a completely filled valence shell
Step-by-step solution
Strictly, helium belongs to the s-block but its positioning in the p-block along with other group 18 elements is justified because it has a completely filled valence shell (1s2) and as a result, exhibits properties characteristic of other noble gases.