Chapter 13, Problem 13.26P

(a)

Interpretation Introduction

Interpretation:

The charge density of an ion and the properties that affect it are to be determined.

Concept introduction:

An ion is the species that have a net electric charge due to loss or gain of electrons.

The cation is an ionic species with a positive charge. It has more protons as compared to electrons so the net charge on the cations is positive. Its symbol is the element with a superscript of the positive charge.

The anion is an ionic species with a negative charge. It has more electrons than protons so the net charge on the anions is negative. Its symbol is the element with a superscript of the negative charge.

(b)

Interpretation Introduction

Interpretation:

The order of increasing charge density is to be ranked.

Concept introduction:

The charge density is the density of charge around the ion. It is the ratio of ionic charge to the volume of ion. The ionic charge and size affect the charge density of the ions.

(c)

Interpretation Introduction

Interpretation:

The effect of ionic charge and size on the ionic heat of hydration is to be determined.

Concept introduction:

The enthalpy is the thermodynamic property of the system. It is defined as the sum of internal energy and the product of pressure and volume of the system. It is a state function and is independent of the path followed by the system from initial to the final state. It is an extensive property. The total enthalpy of the system can not be measured directly so the change in enthalpy $\left(\Delta H\right)$ is measured. If $\Delta H$ of the reaction is positive, it is an endothermic reaction and if $\Delta H$ of the reaction is negative, it is an exothermic reaction.

The enthalpy change of hydration is the enthalpy change when one mole of the ionic species is dissolved in water to give a solution of infinite dilution. It is represented by $\Delta H_{\text{hydration}}$. It is always negative.