Chapter 7, Problem 61A

Interpretation Introduction

Interpretation: The formation of ionic bonds needs to be explained.

Concept introduction:

Molecules are bound together by different types of bonds namely ionic and covalent. Ionic bonds are formed when there is a complete transfer of electrons from one atom to another. These atoms either lose or gain electrons to become negatively or positively charged ions. The forces of attraction between these ions cause ionic bond formation.

Answer to Problem 61A

Ionic bonds are formed when there is a force of attraction between a positively charged ion and a negatively charged ion.

Explanation of Solution

Ionic bonds involve the transfer of electrons from one atom to the other. Another main aspect of the ionic bond is that its formation takes place when there is the presence of an electron donor and an electron acceptor. It is mostly the metal atoms, and electrons donor, that loses electrons to form a positively charged ion while the non-metal atoms, electron acceptor that gains electrons to form negatively charged ions. During the process of donating or gaining electrons, the atoms follow the octet rule to attain a stable noble gas configuration. Therefore, the charges on the anion and cation depend on the electrons lost or gained giving a net charge of zero.

Example: Sodium is metal that has an atomic number as 11 and electronic configuration as ${\text{1s}}^{2}2{\text{s}}^{2}2{\text{p}}^{\text{6}}3{\text{s}}^1$ . It will lose the outermost electron to become a positive ion.

  $\text{Na}\stackrel{-1e^{-}}{\to }{\text{ Na}}^{+}$

Chlorine is a non-metal that has an atomic number of 17 and electronic configuration as ${\text{1s}}^{2}2{\text{s}}^{2}2{\text{p}}^{\text{6}}3{\text{s}}^{2}3{\text{p}}^5$ . It needs one more electron to get an octet configuration. Therefore, it will accept one electron to become a negatively charged ion.

  $\text{Cl}\stackrel{+1e^{-}}{\to }{\text{ Cl}}^{-}$

When the two ions are at an interatomic distance there is an attraction between the two oppositely charged ions which forms an electrostatic bond releasing energy.

  

It can be observed that the net charge is zero.

Conclusion

Ionic bonds are formed when there is a force of attraction between atoms which are positively charged ion and negatively charged ions.