Properties of Solids
Physical properties
• While solid has definite shape and volume; it
does have various other properties that can
be very different. Such as density, colour,
melting points, etc
Pg. 119
Ionic solids
• Lots found in nature as rock and mineral
deposits:
– Sodium chloride (salt)
– Potassium chloride (potash)
• Also found at home:
– Household cleaners (contains sodium hydroixde)
• Other examples:
– Rust (iron (III) hydroxide)
– Tarnish (silver sulfide)
Cont’d
• Some reactive metals don’t occur in elemental
form in nature, they are found as ionic
compounds
• Ionic compounds are also used to extract
metals from naturally occurring compounds
• For example: iron is the most common metal
used but is also very reactive
Formation
• Formation reaction of a metal and nonmetal
similar to sodium chloride
• Formation reaction of two compounds
• Ionic compound stability is similar to that of
noble gases so it can be suggested that there
is a total electron transfer occurring.
A model
• At SATP, all ionic compounds are solid so they
must be held together (bonded) in that rigid
structure.
• Models show that the ions are arranged in a
regular pattern, depending on the size, shapes
and charges
• This is called a crystal lattice
Ionic Compounds
• Ionic compounds are brittle – the ions don’t
rearrange
• Binary ionic compounds also have medium to
high boiling points
• Polyatomic ions have more complex crystal
lattices but the ions have covalent bonds so
can be treated like an monatomic ion
Metallic Crystals
• Shiny, silvery, flexible solids with good
electrical and thermal conductivity
• Hardness varies greatly as well as the melting
temperature
• X-Ray diffraction shows that all metals have a
continuous and compact crystalline structure
Metal Properties
• Metallic bonding – continuous electron clouds
– Low electronegativity – loosely holding electrons
– Empty valence orbitals explains electron mobility
– Strong Electrostatic attraction for bonding
– this gives the many different properties to metallic
compounds
Pg. 124
Molecular crystal
• Elements or compounds
• Small molecules for solid crystal, low melting
point, not very hard, nonconductors
• Properties can be explained by the IMF and
structure
Covalent Network Crystals
• Crystal substances
– Diamond and quartz – very hard
• Very hard, high melting point, brittle,
insoluble, nonconductors
• Examples – silicon carbide SiC(s) used in
sandpaper,
Carbon
• Carbon is extremely versatile with bonding in
various ways
Semiconductors
• Crystalline silicon or germanium ‘doped’ with
a Group 13 or 15 element
• Little bit of energy to put an electron into a
higher orbital and conduct electricity
• Used in transistors, solar cells
Summary
Unit Test Review Summary
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Lewis Formulas
Bonding Theory (types)
Electronegativity
Molecular Formulas (Lewis, structural, sterochemical)
Bonding capacity
VSEPR
Bond and molecular Polarity
Intermolecular Forces
– Isoelectronic Compounds
• Boiling points
• Properties of Liquids and Solids
Suggested review questions
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Pg. 137 #3, 6, 7, 10, 12, 14
Pg. 138 #21, 25, 28
Pg. 139 #35, 40, 41, 43
Pg. 140 #48, 53, 57
Pg. 141 #60