Chapter 11, Problem 55A

(a)

Interpretation Introduction

Interpretation: In the given options the elements (Na, Rb and Cs) with least ability to gain or lose electron is to be mentioned.

Concept Introduction: When moving down the group, the tendency of an atom to lose the electron increases. This is the result of increase in its electropositive nature. This also implies that the atoms of the element present at the top of the group will be better at gaining electrons than the ones present at the bottom.

Explanation of Solution

All these elements belong to group 1 of the periodic table with Na at the top, Rb in middle and Cs at the bottom. Since, the atoms of the element present at the top of the group will be better at gaining electrons than the ones present at the bottom, Na shows the least ability to lose electrons and Cs shows least ability to gain electrons.

(b)

Interpretation Introduction

Interpretation: In the given options the elements (Be, Ca and Ba) with least ability to gain or lose electron is to be mentioned.

Concept Introduction: When moving down the group, the tendency of an atom to lose the electron increases. This is the result of increase in its electropositive nature. This also implies that the atoms of the element present at the top of the group will be better at gaining electrons than the ones present at the bottom.

Explanation of Solution

All these elements belong to group 2 of the periodic table with Be at the top, Ca in middle and Ba at the bottom. Since, the atoms of the element present at the top of the group will be better at gaining electrons than the ones present at the bottom, Be shows the least ability to lose electrons and Ba shows least ability to gain electrons.

(c)

Interpretation Introduction

Interpretation: In the given options the elements (F, Cl and Br) with least ability to gain or lose electron is to be mentioned.

Concept Introduction: When moving down the group, the tendency of an atom to lose the electron increases. This is the result of increase in its electropositive nature. This also implies that the atoms of the element present at the top of the group will be better at gaining electrons than the ones present at the bottom.

Explanation of Solution

All these elements belong to group 17 of the periodic table with F at the top, Cl in middle and Br at the bottom. Since, the atoms of the element present at the top of the group will be better at gaining electrons than the ones present at the bottom, F shows the least ability to lose electrons and Br shows least ability to gain electrons.

(d)

Interpretation Introduction

Interpretation: In the given options the elements (O, S and Te) with least ability to gain or lose electron is to be mentioned.

Concept Introduction: When moving down the group, the tendency of an atom to lose the electron increases. This is the result of increase in its electropositive nature. This also implies that the atoms of the element present at the top of the group will be better at gaining electrons than the ones present at the bottom.

Explanation of Solution

All these elements belong to group 16 of the periodic table with O at the top, S in middle and Te at the bottom. Since, the atoms of the element present at the top of the group will be better at gaining electrons than the ones present at the bottom, O shows the least ability to lose electrons and Te shows least ability to gain electrons.