Properties of Solids

Crystalline and Amorphous

two classifications of solids based on the arrangement of their particles

Crystalline solids

made up of highly ordered particles (ions, atoms, molecules) with a well-defined pattern

Crystalline solids

made up of repeated small units of well-ordered particles that represent characteristics of the crystals called the unit cell

Unit Cell

conforms a certain crystal lattice which is categorized by the distance between particles and angles formed upon stacking of the particles

Melting Point

the temperature at which a solid starts to become liquid, has a direct relationship with the strength of intermolecular forces

Electrical Conductivity

the ability of a material to allow flow of electric current

Electrical current

flows on a material with change particles

Thermal Conductivity

the ability of material o allow transfer of heat

Ionic, Molecular, Metallic, Network Solids

4 Classifications of Crystalline Solids

Ionic Solids

made up of oppositely-charged particles called ions linked by electrostatic interaction called ionic bonds

Hardness and Brittleness of Ionic Solids

Due to the strong ionic bonds acting between ions; the application of external forces can disrupt such attractive forces

Melting Point of Ionic Solids

Usually high since the energy needed to overcome the strength of ionic bonds is high

Electric and Thermal Conductivity of Ionic Solids

It does not conduct electricity in the solid state since every ion in the crystal is fixed in position as a result of the interaction with neighboring ions of opposite charge

Electrical Conductivity of Ionic Solids

Once a solid is divided in a substance, ions are mobile and can freely move, thus allowing flow of electricity

Molecular Solids

consists of molecules interacting with other via IMF (london dispersion forces, dipole-dipole forces, and hydrogen bonds)

Hardness of Molecular Solids

Generally soft solids due to weak IMF that may be disrupted in the presence of external forces like pounding or grinding

Melting Point of Molecular Solids

Melting point is relatively lower since IMF are weaker than ionic bonds

Electrical and Thermal Conductivity of Molecular Solids

Does not conduct electricity either in solid, molten, and aqueous states since these compounds are electrically neutra

Metallic Solids

made up of atoms that are linked by a different type of chemical (metallic) bonds

Metallic Solids

atoms are arranged in a well-ordered manner is immersed in a “sea” of delocalized electrons (electrons spread over two or more atoms)

Hardness of Metallic Solids

Are generally hard due to strong, cohesive forces acting among atoms; the strength of bonds renders metals’ ductility and malleability

Melting Point of Metallic Solids

Its melting point varies and melting causes the atoms to move

Network Crystals

made up of atoms linked by covalent bonds to form an extensive three-dimensional network

Hardness of Network Crystals

These solids are harder than the other types of crystals, owing to strong covalent bonds linking the atoms

Melting Point of Network Crystals

Have very high melting points as enourrmous amounts of energy can break covalent bond linking the atoms

Amorphous Solids

consists of particles that lack a definite order

Melting Point of Amorphous Solids

Melts within a temperature range due to different strength of forces occurring between particles at different sites of the material

Amorphous Solids

Because of the low order, they shatter into irregularly-shaped patterns