Question

Which element has a larger atomic radius? K or Ca
Explain

Answer 1

Potassium (K) has a greater atomic radius than that of Calcium (Ca) because when we move down a group, the atomic radius increases and when we move from left to right in a period, the atomic radius decreases.

Explanation

Both potassium and calcium belong to the 4th period in the periodic table of chemical elements. So, we cannot judge thier atomic radius by their group now, so we have to look at which element to to the left of the other. Here in this case we see potassium is on the left to calcium. So, the atomic radius of potassium (K) is greater than that of calcium (Ca).

Hope this answer correct :)

Answer 2

k )because when we move from left to right in a period, no. of electrons and protons increase one by one but valance shell remains same thus increasing net atomic charge on electrons which makes valance shell shrink and so, atomic radius decreases when going left to right in a period.