Ch.2: Bonding Flashcards
What are the properties of Physical Reactions?
-The product has same properties as the substances in the beginning
-Easily reversible ⇌
What are examples of physical reactions?
Examples:
Melting, Evaporation, Sublimation, Condensation, Dissolving
What are properties of Chemical Reactions?
-New substances formed with different characteristics
-Irreversible or cannot easily be reversed
What are examples of chemical reactions?
Examples:
Photosynthesis, Combustion (burning), Rusting, Respiration, Neutralization
Define ionic bonding:
Electrostatic attraction force between positive and negative ions
How does ionic bonding happen?
By the total transfer of electrons from metals to non-metals
Remember that →
Metals → loose electrons → Positive ions → Cations
Non-metals → gain electrons → Negative ions → Anions
Define lattice:
3D regular arrangement between alternating positive & negative ions
Properties of Ionic Compounds:
- Hard/Strong
- High b.p & m.p
- Soluble in water
- Can conduct electricity only when molten or aqueous
Why do ionic compounds have high melting & boiling points?
Due to presence of strong electrostatic attraction force between ions that need high energy to break up the lattice
Why can ionic compounds conduct electricity/heat only when molten or aqueous?
As there are free moving ions in molten/aqueous while ions are fixed in lattice when solid and thus are not free moving.
What is simple covalent bonding?
Involves the sharing of electrons between non-metals and each-other OR non-metals & hydrogen
Properties of simple covalent compounds:
- Liquids/Gases
- Insoluble in water
- Can’t conduct electricity → No free moving electrons
- Low b.p & m.p (Volatile)
Why are simple covalent compounds simple?
Due to weak intermolecular forces that need low energy to break
Remember that →
There are no weak covalent bonds. All covalent bonds are strong!
What is the bonding in graphite?
Each carbon bonded to 3 carbon atoms by strong covalent bonds forming
layers of hexagons
Properties of Graphite:
- Soft & Slippery
- High m.p & b.p
- Can conduct electricity
Uses of Graphite:
Pencils & lubricants → as it is soft & slippery
Electrodes → As they conduct electricity
Why can graphite conduct electricity?
Have free moving electrons
Why is graphite soft & slippery?
Layers slide over each-other due to weak wander waal forces
What is the bonding in diamond?
Each carbon bonded to 4 carbon atoms in tetrahedral structure by
strong covalent bonds
Properties of diamond:
- Hard & Strong
- High m.p & b.p
- Can not conduct electricity
Uses of Diamond:
Jewelry → Shiny appearance
Cutting & Drilling → Hard & Strong
Why is diamond used in drilling & cutting? (Hard & Strong)
Each carbon bonded to 4 carbon atoms in tetrahedral structure by strong covalent bonds
What is the bonding in SiO2?
Each silicon atom is bonded to 4 oxygen atoms while each oxygen atom is bonded to 2 silicon atoms.
Properties of SiO2:
- Hard & Strong
- High m.p & b.p
- Can not conduct electricity
Uses of SiO2:
- Glass
- Sandpaper
Why is the silicon oxide formula SiO2 not SiO4?
Each silicon atom is bonded to 4 oxygen atoms while each oxygen atom is bonded to 2 silicon atoms.
Define Metallic Bonding
Electrostatic attraction force between layers of positive ions and a sea of free moving electrons
Properties of metals:
- Solids at r.t.p
-Malleable (can be shaped)
-Ductile (drawn into wires)
-Conduct heat & electricity
Why are metals malleable?
Layers of ions slide over each other without breaking metallic bond
