Chapter 11, Problem 49A

Interpretation Introduction

Interpretation: Similarities among elements of group 1 is to be stated.

Concept introduction: Periodic table is an arrangement where elements are arranged on the basis of their increasing atomic number. It consists of 18 group and 7 periods. Most basic classification of atoms is into metal and non metal. Metal are electropositive and non metals are electronegative.

Answer to Problem 49A

In Group 1 of periodic table, all elements are metals. All are highly electro positive among all elements of their respective period. Each element has 1 electron in their valence shell and therefore can easily lose it to attain noble configuration. Due to their lower energy of ionization, they have low melting temperature and soft in nature.

Explanation of Solution

Group 1 of periodic table is known as alkali metals since on reaction with water they form metal hydroxide. Metal hydroxides are alkaline in nature. Members of alkali family are Li, Na, K, Rb, Cs. All are highly electro positive among all elements of their respective period. Each element has 1 electron in their valence shell and therefore can easily lose it to attain noble configuration. There reactivity increases on coming down the group as pull of nuclear charge on valence shell lowers on valence electrons and atomic size increases. Due to their lower energy of ionization, they have low melting temperature and soft in nature.

Conclusion

In Group 1 of periodic table, all elements are metals. All are highly electro positive among all elements of their respective period. Each element has 1 electron in their valence shell and therefore can easily lose it to attain noble configuration. Due to their lower energy of ionization, they have low melting temperature and soft in nature.