Chapter 11.4, Problem 7RQ

Interpretation Introduction

Interpretation: The general trends of atomic size and ionization energies across rows and down columns of the periodic table needs to be explained.

Concept introduction: The ionization energy of an atom is the energy required to remove an electron from an individual atom in the gas phase:

Answer to Problem 7RQ

In rows, atomic number will decrease and ionization energy increases.

In columns, atomic number increases and ionization energy decreases.

Explanation of Solution

In rows, while going down left to right in periodic table the atomic number will be decreases and the number of electrons will increases and shell decreases and ionization energy in increase.

  $\uparrow \downarrow \text{Ionisaztion}\propto \frac{1}{\text{Atomic}\text{size}\uparrow \downarrow }$

In groups, while going up to down the atomic size increases because the number of shell increases and ionization energy decreases.

Conclusion

Periodic table is designed according to atomic number.