NEETChemistryClassification of Elements and Periodicity in Properties
Why do alkali metals and halogens exhibit an increase in atomic size as you descend the groups?
Options
- ABecause they have fewer valence electrons
- BBecause they have a higher effective nuclear charge
- CBecause the inner energy levels are filled with electrons
- DBecause they have a lower atomic number
Correct answer
C. Because the inner energy levels are filled with electrons
Step-by-step solution
As you descend the groups for alkali metals and halogens, the increase in atomic size is due to the inner energy levels being filled with electrons, which shield the outer electrons from the nucleus.