1. Types of Solids
SCH 4U1

2. Types of Solids We will classify solids into four types: Ionic Solids
Metallic Solids
Molecular Solids (Non Polar and Polar)
Covalent network solids (3D and 2D)

3. Ionic Solids
An ionic solid is a solid that consists of cations and anions (Latice point particles) held together by the electrical attraction of opposite charges (ionic bonds)
This is technically considered an intra-ion , 3D force, and results in ionic compounds having very high melting points as a great amount of energy is required to separate the ions.

4. Ionic Solids con’t
Most are water soluble due to the formation of ion-dipole attractions.
These solutions are electrolytes, as the ions are mobile.
Can form basic and acid solutions.
No conductivity in solid form as the ions are in fixed lattice positions.
Can be magnetic if solid contains Fe, Co or Ni ions.

5. Arrangement of Ions in a Sodium chloride crystal

6. Metallic solids
In metals, the valence electrons of neighbouring positive kernals form a sort of ‘electron sea’
These electrons are called “delocalized electrons”
This ‘delocalized electron soup’ can be thought of as a ‘glue’ that holds the positive nuclei of the metal atoms together. The metallic bond.

7. Metallic solids
Metals usually have high melting points, although this can be highly variable.
Conduct heat and electricity due to mobile electrons.
Can be magnetic is made of Fe, Co or Ni.
Insoluble in water.

8. Different Types of Crystal Lattices

10. Gallium

12. Molecular solids
A molecular solid is a solid that consists of atoms or molecules held together by intermolecular forces
Examples include:
Solid neon (melting point of -248oC)
Solid CO2 (dry ice)
Solid H2O (ice)
Iodine
Sugar

13. Molecular solids – Non-polar
I2 is non-polar, so it has only London Dispersion forces
However, it has 106 electrons, giving it sufficient IMF to be a solid at room temperature.
Weak IMF leads to lowest melting points.
No mobile electrons, so no electrical conductivity
Insoluble in water due to lack of polarity.

15. Molecular solids - Polar
Have stronger IMFs of dipole- dipole forces and Hydrogen Bonding forces.
Same electrical properties as non- polar.
Both water solubility and melting points are greater.
Can form acidic or basic solutions.

16. Covalent Network Solid - 3D
Highest melting point as all atoms are covalently bonded.
Hard, generally crystalline or “glassy” appearance
No water solubility
No electrical or heat conductivity.

17. Silica glass (SiO2)

18. Amethyst quartz (SiO2)

19. Graphite - 2D network solid
It consists of ‘sheets’ of covalently bonded atoms
It has a melting point lower than 3D, they are softer and usually shiny
It is also an electrical conductor in one direction only because of delocalized electrons between sheets of atoms.
Insoluble in water.

22. Graphite, Diamond and Silicon dioxide (Silica)