Chapter 7.4, Problem 40SSC

Interpretation Introduction

Interpretation: The contrast between the structure of ionic compounds and metals.

Concept introduction:

The packing of molecules or atoms is usually at its lattice through networks wherein there is an interaction between the molecules. Based on the strength of interaction, the bonds are further classified as ionic, hydrogen bonding, metallic bonding and covalent bonding.

Answer to Problem 40SSC

The main difference in structure is that metals are having metal ions immersed in a sea of electrons, whereas ionic compounds are those having positive and negative charges occupying lattices

Explanation of Solution

The bonding in metals is formed when the electrons in the metal leave its outer shell to form a positively charged ion. These ions are then amidst a ‘sea’ of delocalized electrons. The structure is such that metals consist of metals ions arranged at lattice points in a regular pattern.

  

The bonding in ionic compounds is merely electrostatic forces of attraction between the positively charged ion and negatively charged ion. The metal atom will lose electron(s) to form a positive ion while a nonmetal atom will gain electron(s) to form a negative ion. Both are held by coulombic forces to give a brittle structure.

  

The oppositely charged ions are next to each other forming a regular pattern.

Difference in structure

Metals	Ionic compounds
The positively charged ions occupy lattice points which are surrounded by a ‘sea’ of electrons.	The positively charged ions are situated next to negatively charged ion and are arranged in a regular pattern.
The electrons are ‘delocalized’ over the entire lattice and are free to move about.	The electrons are not delocalized and there are no free electrons.
The forces of attraction are electrostatic forces between a metal ion and delocalized electrons.	The forces of attraction are electrostatic forces between two oppositely charged ions.

Conclusion

The main difference in structure is that metals are having metal ions immersed in a sea of electrons whereas ionic compounds are those having positive and negative charges occupying lattices.