The correct decreasing order of atomic radii (pm) of Li, Be, B and C is
- Be > Li > B > C
- Li > Be > B > C
- C > B > Be > Li
- Li > C > Be > B
Answer
(2) Li > Be > B > C
Solution
Li, Be, B and C are in the same period (period 2).
Across a period the nuclear charge increases while electrons enter the same shell, so the atomic radius decreases from left to right.
Atomic radii: Li (152 pm) > Be (111 pm) > B (88 pm) > C (77 pm)
Order: Li > Be > B > C
Answer: (2)