Question

Among the elements $Li,N,C$ and $Be$, one with the largest atomic radius is:

• A. $Li$
• B. $N$
• C. $C$
• D. $Be$

Answer 1

The correct option is A $Li$

Along a period, increase in nuclear charge (Z) of atoms (by one) is more than the shielding effect of each electron, added to the same shell ($n=2$). Therefore, the effective nuclear charge increases along a period and results in decreasing atomic radii. Among $Li,N,C,Be$, $Li$ has the largest atomic radii.

Option $A$ is the correct choice.