Question

As compared to Potassium, Sodium has:

• A. Lower electronegativity
• B. Lower melting point
• C. Higher ionization potential
• D. Greater atomic radius

Answer 1

The correct option is C

Higher ionization potential

The correct option is (C):

Explanation for the correct answer:

Higher ionization potential:

1. Basically, Sodium has three orbits and Potassium has four orbits.
2. So, lesser the distance of the orbits from the nucleus the higher energy would be required to remove the outermost electron and vice versa.
3. Therefore, more the energy required to remove an electron from Sodium than from the Potassium.
4. Hence, the ionization energy of Sodium is higher than the Potassium.
5. Also the electron in Potassium is also more affected by the shielding due to the more shells and so further on weakening this attraction.
6. Which all means that the less energy would be needed to remove the outermost electron and so the ionization energy would be lower for Sodium.

Explanation for the incorrect options:

Option (A):

Lower electronegativity:

1. Electronegativity is basically the tendency of an atom just to attract the shared pair of electrons towards itself.
2. In the periodic table, on moving from left to right in a period there would be an increase in the electronegativity.
3. And on move from top to bottom in a periodic table it will decrease.
4. So the electronegativity of Sodium is greater than Potassium.
5. Hence, this is an incorrect option.

Option (B):

Lower melting point:

1. So, in a periodic table going from top to bottom, there would be an increase in the size of atom.
2. As there is an increase in the size of atom, so the metallic bond will start weakening.
3. Therefore, Sodium has high melting point than the Potassium because of the stronger metallic bonding.
4. Hence, this is an incorrect option.

Option (D):

Greater atomic radius:

1. On moving down the group, there is an increase in the shell of the atom.
2. So Potassium basically has an extra electronic shell than the Sodium.
3. So because of the presence of that shell, the atomic size of Potassium is greater than Sodium.
4. Hence, this is an incorrect option.

Therefore, the correct option is (C): Higher ionization potential