Chapter 9, Problem 5STP

Interpretation Introduction

Interpretation:

The correct two atomic properties that follow the same trend while moving down a group on the periodic table needs to be determined.

Concept introduction:

Ionization energy is the energy required to overcome the attraction between the positive charge of the nucleus and the negative charge of the electron.

Answer to Problem 5STP

Option B is correct.

Explanation of Solution

Reason for correct option: Atomic radii increase down the group. On moving top to bottom in a group, the size of the atom increases along with th principal energy level; thus, the atom becomes larger. Hence, the outer electrons are distant from the nucleus. This increased distance counteracts the pull of the increased nuclear charge.

On moving down a group, the valence electrons are present in higher principal energy levels, resulting increase in ionic size. Therefore, the ionic radii increases down a group for both positive and negative charged ions.

Therefore, atomic radius and ionic radius follow the similar trend on the periodic table.

Conclusion

Reason for incorrect option: Ionization energy decreases down the group because atomic size increases down the group. Therefore, atomic radius and ionization energy do not follow same trend. Hence, option A is incorrect.

Also option C is not correct because ionization energy and ionic radius do not follow the same trend. Hence, option C is not correct.

Electronegativity decreases down the group on periodic table because the distance between nucleus and outermost shell increases. Therefore, electro negativity and ionic radius do not follow the same trend on periodic table. Hence, option D is incorrect.