Understanding Atomic Radius
Atomic radius refers to the size of an atom, typically measured from the nucleus to the boundary of the surrounding cloud of electrons. The atomic radius varies across the periodic table based on several factors.
Trends in Atomic Radius
- Increases Down a Group: As you move down a group in the periodic table, the atomic radius increases. This is due to the addition of extra electron shells, which outweighs the increase in nuclear charge.
- Decreases Across a Period: As you move from left to right across a period, the atomic radius decreases. This is because of increasing nuclear charge, which pulls electrons closer to the nucleus.
Comparison of Elements
Now, let’s analyze the given elements:
- Lead (Pb): Located in Group 14, Period 6. It has a relatively large atomic radius due to being lower in the periodic table.
- Chlorine (Cl): Found in Group 17, Period 3. It has a smaller atomic radius compared to Pb and Na because it is further right in the periodic table.
- Sodium (Na): Positioned in Group 1, Period 3. Sodium has a larger atomic radius than chlorine but is still smaller than lead.
- Sulfur (S): Located in Group 16, Period 3. It has a smaller atomic radius than both Na and Cl.
Conclusion: Maximum Atomic Radius
Among these elements, Sodium (Na) has the maximum atomic radius. This is primarily due to its position in Group 1, where elements have larger radii compared to those in the same period but in other groups. Thus, the correct answer is option 'C' (Na).