Question

Which of the following elements has the largest atomic radius?

Answer 1

Answer:

            Potassium has the largest atomic radius.

Explanation:

                        Using periodic table trends one can easily compare the atomic radii of elements. The trends in atomic radii are as follow,

Trends in Groups:

                             Moving from top to bottom along the groups the atomic radii increases because as you move from top to bottom the number of shells increases hence, the distance of valence electrons from nucleus also increases and therefore, atomic radius increases.

Trends is Periods:

                             Moving from left to right along the periods the atomic radii decreases. This is because the number of protons and electrons increases but the the valence shell remain the same hence, causing more nuclear charge and more attraction between the valence electrons and nucleus.

Result:

           Potassium, Calcium, Cobalt and Nickle all are present in same period. Potassium present at the extreme left will have greater atomic radii of 0.227 nm while Co and Ni at the middle of period will have atomic radii of 0.125 nm each. While, the atomic radius of Calcium next to K is 0.197 nm.