Chapter 11, Problem 1RQ

Interpretation Introduction

Interpretation:

The given elements have to be arranged in their increasing order of atomic radii.

Concept Introduction:

Atomic radii:

The distance between the centers of the nucleusand the outermost electrons is known as the atomic radius of an atom.  In the periodic table, across a period atomic radius decreases and it increases down a group.

Explanation of Solution

Given elements,

Sodium $\text{(Na)}$, Magnesium $\text{(Mg)}$, Chlorine $\text{(Cl)}$, Potassium $\text{(K)}$ and Rubidium $\text{(Rb)}$.

In the periodic table, across a period atomic radius decreases and it increases down a group.

In the given elements, Sodium belongs to Group 1A and third period of the periodic table, Potassium belongs to Group 1A and fourth period of the periodic table and Rubidium belongs to Group 1A and fifth period of the periodic table.

So, the order will be $\text{Na}\text{<}\text{K}\text{<}\text{Rb}$.

The remaining two elements Magnesium and Chlorine are belong to third period of the periodic table but Magnesium is Group 2A element and Chlorine is Group 7A element.

So the order will be $\text{Cl}\text{<}\text{Mg}$.

Therefore, the increasing order of atomic radius of the given elements are shown below,

  $\text{Cl}\text{<}\text{Mg}\text{<}\text{Na}\text{<}\text{K}\text{<}\text{Rb}$