Chapter 11, Problem 5STP

Interpretation Introduction

Interpretation: The correct trend of ionization energy across a row on the periodic table needs to be determined.

Concept interpretation: Ionization energy is the amount of energy required to remove an electron from an outer shell of atom.

Answer to Problem 5STP

Option A is correct.

Explanation of Solution

Ionization energy of an atom increases left to right in a period because the electrons are held tighter and have higher effective nuclear charge. Due to increase in number of electron and shell remains the same.

Conclusion

On moving across a period in periodic table, the ionization energy increases because the electrons are much tightly packed to the nucleus due to high effective nuclear charge.

Other options don’t follow the periodic trends for ionization energy.