Lesson 5 CHEM - Types and Properties of Solids

Question 1

Solids are generally held together by

Answer 1

IONIC or strong COVALENT bonding, and the attractive forces between the atoms, ions, or molecules in solids are VERY STRONG

Question 2

• The solids in which the particles are not arranged in any specific order or the solids that lack the overall order of a crystal lattice are called amorphous solids.
• Though their molecules are close together and have little freedom to move, they are NOT ARRANGED IN A REGULAR ORDER as are those in crystalline solids.
• Common examples of this type of solid are glass, rubber, wax, gels, and plastics.

Answer 2

Amorphous

Question 3

• The solids featuring highly ordered arrangements of their particles (atoms, ions, and molecules) in microscopic structures are called crystalline solids.
• The smallest repeating pattern of crystalline solids is known as the UNIT CELL, and unit cells are like bricks in a wall — they are all identical and repeating.
• Common examples of this type of solid are diamond, metals, table salt, sugar, and ice.

Crystalline solids can be further classified into molecular, ionic, metallic, and covalent solids. The variation in the relative strengths of these four types of interactions correlates nicely with their wide variation in properties.

Answer 3

Crystalline

Question 4

• Made up of metal atoms that are held together by metallic bonds
• can be soft to hard
• High melting points
• Good conductors of electricity
• Good thermal conductors
• Malleable and ductile
• Platinum (Pb)
• Gold (Au)
• Copper (Cu)
• Tungsten (W)
• Iron (Fe)

Answer 4

METALLIC

Question 5

• Made up of positive and negative ions and held together by electrostatic attractions
• Brittle, hard
• Very high boiling and melting points
• Poor electrical and thermal conductors in the solid state, good conductors in liquid statE
• Table salt, sodium chloride (NaCl)
• Calcium fluoride (CaF2)
• Silver chloride (AgCl)
• Copper sulfate (CuSO4)
• Magnesium oxide (MgO)

Answer 5

IONIC

Question 6

• Made up of atoms connected by covalent bonds; the intermolecular forces are covalent bonds as well
• Very hard
• Very high melting points
• Graphite
• Diamond
• Quartz or silicon dioxide (SiO2)
• Silicon carbide
• Transition elements

Answer 6

COVALENT/NETWORK

Question 7

• Made up of atoms or molecules held together by London dispersion forces, dipole-dipole forces, or hydrogen bonds
• Soft
• Low to moderate melting points
• Low flexibility
• Poor thermal and electrical conductors
• Hydrogen (H2)
• Iodine (I2)
• Dry ice (CO2)
• Silicon tetrachloride (SiCl4)

Answer 7

MOLECULAR

Question 8

Molecular Solids
* Soft
* Insulator of electricity
* Very low melting point
* IMF – LDF
* Examples: Ar, CCl4, H2, CO2

Answer 8

Non-polar MOLECULAR SOLIDS

Question 9

• Soft
• Insulator of electricity
• Low melting point
• IMF – LDF and Dipole-dipole
• Examples: HCl, SO2

Answer 9

POLAR MOLECULAR SOLIDS

Question 10

• Hard
• Insulator of electricity
• Low melting point
• IMF – LDF, Dipole-dipole: H-bond
• Examples: H2O

Answer 10

HYDROGEN-BONDED MOLECULAR SOLIDS