Topic 1.3- Key concepts/ types of a substance Flashcards
Types of a substance
Why can elements be classified as Ionic, Simple/giant covalent, or metallic.
-Different atoms cuase different bonds:
- Ionic, Covalent or metallic bonds.
What is an ionic structure?
- Gas (non-metal) and a metal
- Held together by strong electrostatic forces between charged ions
- E.g magnesium oxide
What is a simple molecular structure?
- Strong covalent bonds between thee atoms of the molecules
- Weak intermolecular forces between the molecules (e.g water)
What is a giant covalent structure?
- Covalent bonds form one structure
- Graphite, diamond
What is a metallic structure?
- Lattice of positive metal ions
- and free electrons
- Strong electrostatic forces of attraction
What and why is Ionic melting point?
-High
-Strong electrostatic forces between the positive metal and negative gas
What and why is simple molecular melting point?
-Low
-Covelant
-Weak intermolecular forces between molecules
What and why is giant covalent melting point?
-High
-It is NOT A molecule and therefore has no weak intermolecular forces between molecules
-Strong electrostatic forces
What and why is Metallic melting point?
-High
-Strong electrostatic forces between delocalised electrons and positive ions.
What and why is Ionic bonds physical state?
-solid
-high melting point
What and why is simple molecular bonds physical state?
-gas
-low melting point
What and why is giant covalent bonds physical state?
-solid
-high melting point
What and why is metallic bonds physical state?
-solid high melting point
What and why is Ionic solubility in water?
- Many are soluble
- Water molecules ( electrons are generally closer to oxygen as oxygen has more protons)
- In water Oxygen is more negative and hydrogens are more positive
- Positive metal will move to oxygen
- Negative gas will move to hydrogen
What and why is simple molecular solubility in water?
- Few are soluble
-Water is polar and simple molecular structures are normally non-polar
What and why is/isn’t giant covelant solubility in water?
-Insoluble
-Strong covalent bonds
What and why is metallic solubility in water?
-Insoluble
-Non polar and water is polar
What and why does/ doesn’t Ionic conduct electricity?
-Only in molten form/ in solution
- Ions can move freely
What and why does/ doesn’t simple molecular conduct electricity?
- Most do not
- they are neutral
What and why does/ doesn’t giant covalent conduct electricity?
- Most do not conduct
- Most have no free electrons
What and why does/ doesn’t metallic conduct electricity?
- Can conduct
- Free delocalised electrons
What are two main examples of giant covalent structures made of carbon?
- Diamond
- Graphite
What is the structure of graphite?
- One atom thick
- Light
- Strong
- Conducts electricity
- high melting and boiling point
Why can graphite conduct electricity?
- Graphite is made of three carbon atoms bonded to one carbon atom
- Carbon has 4 electrons on outer shell
- One free electron
- Hexagonal shape
- High melting point
Why does graphite have a high boiling point?
Despite weak intermolecular forces between layers
- Strong covalent bonds
Properties of diamond?
- Very strong
- High melting/ boiling point
- Does not conduct electricity
- rigid lattice structure
Why can’t diamonds conduct electricity?
- Carbon has four bonds each, no free electrons
Why do diamonds have a high melting/boiling point?
- No weak intermolecular forces
- All strong covalent bonds between atoms
Why is diamond used in cutting?
- Strong
- Hard
- strong covalent bonds
Why is graphite used in lubrication?
- Hexagonal sheets can slide past each-other due to weak intermolecular forces.
- Soft, slippery
- High melting point due to strong covalent bonds
Why is graphite used in electrodes?
- Free electron
What is graphene and what are its properties?
thickness, electrical, boiling points
- One layer of graphite
- Conducts electricity (free electrons)
- High melting/boiling point (no layers, no weak intermolecular forces)
What are fullerenes?
-Hollow carbon structures
- Made of hexagonal shapes
( could have parts of 5, or 7 connected, pentagonal or heptagonal)
What was the first fullerene
- Buckminsterfullerene
- 60 carbon atoms
- Ball shape
What are the uses of fullerenes like Buckminsterfullerene?
- Deliver drugs
- Lubricants
- Catalysts
Uses of carbon Nanotubes ?
(rolled graphene sheet)
- Very long, small diameter
- Extremely elastic
- Reinforce materials ( tennis rackets)
Describe poly(ethene)
- C2H4
- chain of carbon that consists of large molecules
- Hydrocarbon
Metals properties?
- Conduct electricity - free delocalised electrons
- Malleable, uniform layers can slide over each-other.
Describe most metals?
- High melting and boiling point
- Shiny
- Conduct electricity well
Describe most non- metals
- Low melting and boiling point
- poor conductors of electricity
Limitations of the dot and cross diagram?
- Not 3-D
- looks like electrons are different
Limitations of the ball and stick diagram?
- Atoms are far apart
- Doesn’t include electrons are protons
Ideas needed to see in models?
- Electrons the same
- Protons
- 3-D
- Bonded and close together
- Respective sizes of atoms
- Number of atoms included
What are nano particles?
-small particle (abt 1nm-100nm)
-Larger than an atom or a molecule
What are nano particles used for?
-sunscrean (very small + absorbant)
-eyeglasses
-crack resistant paint
-drug delivery
-More durable tennis rackets
What are the dangers of nano particles?
- Untested
- Very small can be absorbed by bloodstream
