Chapter U1.10, Problem 7E

Interpretation Introduction

Interpretation:

The two elements which are least reactive needs to be identified from the given options.

Concept introduction:

The elements can be classified on the basis of their metallic nature in three types; metals, non-metals and metalloids.

Metals are the elements which are hard, have high melting point and boiling point, with shiny surface and high reactivity.

Non-metals are the elements which mainly exist in liquid and gas state. They are brittle in nature with moderate or high electronegativity. They are placed on the right side of the periodic table.

Answer to Problem 7E

Correct answer:( a) and (f) are least reactive element.

Explanation of Solution

Given information:

The given options are as follows:

1. Chlorine (Cl)
2. Barium (Ba)
3. Copper (Cu)
4. Rubidium (Rb)
5. Potassium (K)
6. Mercury (Hg)

Reason for correct option: Metals are more reactive elements than non-metals. This is because they have 1, 2, 3 valence electrons which can be lost easily to form metal cations. This makes them more active for other substances. In the given elements, all are metals except Cl. In metals the alkali and alkaline earth metals which are placed in Group-1A and IIA are most reactive whereas transition elements are less reactive.

Thus, in the given metals; Hg must be least reactive as K is alkali metal, Ba is alkaline earth metal. Cu and Hg are transition metals out of which Cu is more reactive than Hg.

Chlorine is a non-metal and thus less reactive than all the given metals.

Conclusion

Reasons for incorrect options: Alkali and Alkaline Earth metals are more reactive metals than transition metals and also metals are more reactive than non-metals.