Question

why is the k+ ion larger in size than the na+ ion?

Answer 1

na+ have 10electrons
but k+ have 18elecrtons
sooo k+ is larger. in size
hope you understand

Answer 2

Na+ has a Pauling ionic radius of 95 pm, while K+ has a Pauling ionic radius of 133 pm.

Reason:

K+ has a larger atomic radius than Na+. In Periodic Table there are many trends. One such trend involves the atomic radius for these elements. As we go down in the same column, the atomic radius increases. As K+ is just below Na+, it has larger radious than Na+.