Bonding, Structure and Properties of Matter Flashcards
What is an ion?
Ions are charged particles that have lost or gained an electron
What groups are most likely to form ions on the periodic table?
Group: 1,2,6,7
When forming an ion what process does a metal go through (group 1 and 2 elements)?
Oxidation the metals lose electrons
When forming an ion what process does group 6 and 7 elements go through?
Reduction the elements gain electrons
Define ionic bonding?
When a metal loses electrons to form a positively charged ion and a non-metal gains these electrons to form a negative ion. The oppositely charged ions are strongly attracted through electrostatic forces.
What is the diagram we use to show ionic bonds?
Dot and cross diagram
What is the structure of an ionic compound?
Giant Ionic Lattice-with closely packed regular lattice arrangement with strong electrostatic forces between each oppositely charged ions in all directions.
What properties do all ionic compounds have in common?
- High MP and BP due to the strong bonds
- No free flowing electrons so they don’t conduct electricity
What is a covalent bond?
When non-metal atoms bond together by sharing electrons. Each covalent bond provides one shared electron until both atoms have a full outer shell.
What makes covalent bonds strong?
The positively charged nuclei are attracted to the shared pair of the electrons by electrostatic forces.
What diagram do you use to display a covalent bond?
You can use a dot and cross diagram where the outer shells merge and the dots of one element merge with the crosses of the other to represent the sharing of electrons.
What is a disadvantage of a dot and cross diagram?
It does not show how they are arranged in space.
What is a simple molecular substance?
Small molecules containing weak covalent bonds they are usually gases or liquids at room temperature
What is a polymer?
A polymer is lots of small units linked by strong covalent bonds to form a long molecule. There inter molecular forces are stronger than simple covalent bonds.
What are the properties of a polymer?
- Weaker intermolecular forces than ionic or covalent so it has a relatively low MP and BP
- Generally solid
What are Giant Covalent Structures?
They are macromolecules where all atoms are bonded by strong covalent bonds.
Give some properties of Giant Covalent Structures?
They don’t conduct electricity because they don’t contain any charged particles so they also don’t conduct electricity when molten
Very high MP and BP
Give 3 examples of a Giant Covalent Structure?
Diamond - four carbon bond
Graphite - three carbon bonds (forms layers)
Silicon dioxide - silicon and oxygen
What is an allotrope?
An allotrope is a different structual form of the same element in the same physical state.
Give some properties of diamonds
Doesn’t conduct electricity as there is no free flowing electrons
High melting point due to the strong 4 carbon bond
Give some properties of graphite
It has a three carbon bond which makes sheets of carbon atoms arranged in hexagons
Three out of each carbons four outer electrons are used in bonds so graphite has delocalised electrons meaning it can conduct electricity and thermal energy
Graphite is soft and slippery - ideal for lubricants
What do we call a single graphite layer?
Graphene and it is very light
What are fullerenes?
Fullerenes are molecules of carbon, shaped like closed tubes or hollow balls
The carbon bonds can be arranged as hexagons, pentagons and heptagons
What are the uses of a fullerene?
Becasue they can be used to trap a molecule inside its enclosed structure like a “cage” it can be used to deliver certain drugs into the body.
They can be used as industrial catalysts because of their huge surface area catalyst molecules can be attached to the fullerenes
They can also be used as lubricants
Give two examples of fullerenes
Buckminsterfullerene
Nanotubes
Give the properties of Buckminsterfullerene
First fullerene to be discovered
Shaped like a closed sphere with a pentagonal and hexagonal arrangement of carbon bonds
It has the molecular formula C60
Give some properties of Nanotubes
They are tiny and long carbon cylinders
They can conduct electricity and thermal energy
They have a high tensile strength (don’t break when stretched)
Give some uses of Nanotubes
They can be used in electronics
They can be used to strengthen materials without adding too much weight such as tennis racket frames
What is metallic bonding?
When metal ions are arranged in a giant lattice the free flowing electrons act as glue and the inter molecular forces form a compound there is electrostatic attraction between the positive metal ions an the negative electrons
Give some properties of metals
They are malleable due to arrangement of atoms in layers.
They are good conductors of electricity and heat - because of their delocalised electrons
They are ductile
What is an alloy?
Pure metals are mixed with other metals to make them harder the new atoms from the metal will distort the layers making it difficult for them to slide over each other.
What is a matter state?
It is the state in which substances form due to how strong the electrostatic forces are within the substance. The stronger the forces the closer together the particles and the more fixed they become (solid). The weaker the attraction the further apart the atoms are (gas).
How do particles move within a solid?
The particles vibrate about their position and when heated they vibrate more.
How do particles move within a liquid?
The particles are constantly moving with random motion. The hotter the liquid gets the faster they move this causes liquids to expand when heated.
How do particles move within a gas?
The particles constantly move with random motion. The hotter they get the faster they move resulting in an expansion or an increase in pressure.
What is the state symbol for solid?
s
What is the state symbol for liquid?
l
What is the state symbol for gas?
g
What is the state symbol for aqueous?
aq - means dissolved in water
How does a solid change matter state to liquid?
Particles gain more energy through heating so they vibrate more when they are at a certain temperature (melting point) the particles break free from their positions. - MELTING
What is the process called when a liquid changes matter state to a gas?
Boiling or Evaporating
What is the process where gas turns into liquid?
Condensation
What is the process when liquid turns into a solid?
Freezing
What is the diameter of a nano-particle?
1nm - 100nm
Give some properties of nano-particles?
- They have a large surface area to volume ratio so they can be an effective catalyst,
- They are very good conductors of electricity,
What is the process of a solid changing directly to a gas?
Sublimation
What are the uses of Nano-particles?
- Catalyst
- Medicines - they can be used to deliver drugs because nano-particles are easily absorbed by the human body,
- can be used in circuits and electric circuits
- can be used in moisturisers to stop to improve them without becoming more oily,
- Sun cream for protection against UV rays - they have better skin coverage and protection than traditional sun creams
What is the main use of silver nano-particles?
Silver nano-particles have antibacterial properties, they can be added to polymer fibres in surgical masks and wound dressings and added to deodorants, They are added in socks.
What are the risks of nano-particles?
- We do not fully understand the effects of nano-particles on our bodies, this means that all products including nano-particles have to go through thorough testing to makes sure they are safe. Could cause an allergic reaction.
- Some people are worried that nano-particles have been used in products before knowing all the risks of using them. Because of this, all products with nano scale particles have to declare this on the packaging.
- It is also unknown if nano-particles damage the environment.
