Question

Considering the size of the parent atom, which ion is predicted to be larger: Na(1+) or K(1+)?

Answer 1

The Na+ ion is predicted to be larger than the K+ ion because cations are always smaller than the neutral atom. The removal of the 3s1 electron in Na+ leads to a smaller ion size compared to K+.

Step-by-step explanation:

The Na+ ion is predicted to be larger than the K+ ion.

Cations are always smaller than the neutral atom. The Na+ ion has a smaller radius than the neutral Na atom because the 3s1 electron has been removed, resulting in a closed shell with n = 2.

On the other hand, the K+ ion is larger than the neutral K atom because the additional electron produces a 4s2 valence electron configuration. Although both Na+ and K+ have the same +1 charge, the removal of the 3s1 electron in Na+ leads to a smaller ion size compared to K+.