Question

Which of the following element has the largest atomic radius?

• A. $\mathrm{Li}$
• B. $\mathrm{Cl}$
• C. $\mathrm{Na}$
• D. None of above

Answer 1

The correct option is C

$\mathrm{Na}$

Explanation for correct option C

1. Atomic radius refers to the size of the atom which can be measured in terms of covalent or metallic radius depending on whether it is a metal or a non-metal.
2. For the second period elements, atomic size decreases across a period.
3. Going from top to bottom, atomic size increases with the atomic number.
4. Since $\mathrm{Li}$ belongs to second period while the other belongs to third period, their size will be greater than that of $\mathrm{Li}$.
5. Now, $\mathrm{Na}$ being on the left of the periodic table will have the greater size.
6. Hence, option C is the correct answer.