Question

Density of sodium and potassium follows the order:

• A. $K<Na$
• B. $K>Na$
• C. $Na\approx K$
• D. None of these

Answer 1

The correct option is A $K<Na$

The density of sodium is higher than the density of potassium. This is due to the unusual increase of the atomic size of potassium due to the presence of 3d-orbital.