Question
What happens to the size of atoms in p-block elements when we move from left to right in the same period?
MHT CET
Chemistry
Classification of Elements and Periodicity in Properties
2026
MHT CET 2026 (15 April Shift 1)
MHT CET Chemistry Question (2026) — Solution
Options
- A. Size does not change
- B. Size increases then decreases
- C. Size increases
- D. Size decreases
Answer
D. Size decreases
Step-by-step solution
As we move from left to right across a period, the atomic number increases, meaning the number of protons in the nucleus increases. The additional electrons are added to the same principal shell, so the shielding effect remains almost constant. This results in an increase in the effective nuclear charge (Z_ eff ), which pulls the valence electrons closer to the nucleus. Consequently, the atomic size decreases from left to right in the same period. Answer: Size decreases
Related: Chemistry — Classification of Elements and Periodicity in Properties · All PYQ Banks