Chapter U1.10, Problem 1E

Interpretation Introduction

Interpretation:

The change in reactivity for the Group IA elements needs to be explained on moving down the group.

Concept introduction:

Element is the basic unit of any substance which can combine with same or different elements to form molecules and compounds. Elements are composed of same type of atoms therefore they exhibit unique physical and chemical properties.

The chemical reaction of two or more elements leads to the formation of new molecules and compounds.

Answer to Problem 1E

As the atomic size increases, the reactivity of metallic element increases.

Explanation of Solution

In the long form of periodic table; alkali metals, alkaline earth metals, halogen and the Noble gases are name of certain groups. In periodic table, the vertical columns are called as groups. Alkali metal are the Group IA or 1^st group elements. These elements forms alkaline oxides and hydroxides.

Moving down the group, the atomic size of elements increases thus, the outermost electron is more easily available for the reaction. Thus, the reactivity of metallic element increases by losing the outermost electron. This is because as the atomic size increases, the nuclear attraction decreases for valence electrons and it becomes easier to excite in different chemical reactions. Therefore, the chemical reactivity increases down in the group.

Conclusion

As the atomic size increases, the reactivity of metallic element increases.