Chapter 15, Problem 16TE

To determine

The reason for potassium atom is larger than the sodium atom.

Answer to Problem 16TE

The potassium atom is larger than the sodium atom because of one extra electron shell present in it.

Explanation of Solution

The size of an atom depends upon the number of protons in its nucleus, number of electrons in its shell and the energy hold by them.

Sodium and potassium atom present in group one of periodic table. The atomic number of potassium is 19 and for sodium is 11. In a potassium atom, 19 electrons and distributed as and for sodium atom, 11 electrons distributed as . The figure of electrons distribution in these atoms is shown below:

Potassium atom have 4 shells of electrons and sodium atom has 3 shells of electrons, so it is clear that the potassium atom has one electron shell extra than sodium. Thus the size of potassium atom is also greater than the size of sodium atom.

Conclusion:

Therefore, the potassium atom is larger than the sodium atom because of one extra electron shell present in it.