Question

If screening effect is not considered, and thus effective nuclear charge is the atomic number then the larger radius out of $Li,Na$ is 11.

(consider only atomic number)

Answer 1

The atomic number of Li is 3 whereas that of Na is 11. The effective nuclear charge of sodium is higher so its atomic radius should be small. But a new shell is added for sodium. Hence, its atomic radius is large.
Hence, the correct answer is 11.