Write the following elements in decreasing order of atomic radius. Li, Cs, K, Rb

Cs > Rb > K > Li

Explanation:

Given elements:

             Li,  Cs , K and Rb

Arrange in the the order of decreasing atomic radius:

Atomic radius is taken as half of the inter-nuclear distance (d) between two covalently bonded atoms of non - metallic elements or half of the distance between two nuclei in the solid state of metals.

So, the given species are the same group on the periodic table. These are group 1 elements;

          Li,  Cs , K and Rb

                   Cs > Rb > K > Li

a) the particles of the chair are strongly held together.