Structure and bonding

• What is an ion?

  A charged particle formed when an atom, or group of atoms, loses/gains electrons
• What is an ionic bond?

  An electrostatic attraction between oppositely charged ions (metal and non metal)
• What is a metal?

  In ionic bonding metals lose electrons to become positively charged ions
• What is a non-metal?

  In ionic bonding, non-metals gain electrons to become negatively charged ions. Located on the right hand side of the periodic table.
• What is a giant lattice?

  A large regular 3D structure that contains millions of bonds
• What is a covalent bond?

  A bond formed when non-metals share electrons. An electrostatic attraction between the positively charged nuclei of the bonded atoms and the electrons shared between them.
• What is a molecule?

  A small group of covalently bonded atoms. Not charged.
• What is a polymer?

  Very large covalently bonded molecules with many repeating units.
• What is metallic bonding?

  The bonding of metals consists of a lattice of positive ions surrounded by a sea of delocalised electrons. The metallic bond is the electrostatic attraction between the positive ions and the delocalised electrons.
• What is an alloy?

  A mixture of two or more metals. At least one is a metal. E.g. steel is a mixture of iron and carbon.
• List the main physical properties of diamond and graphite.

  Diamond: high melting and boiling point, insoluble, hard, do not conduct electricity

  Graphite: soft, high melting point, can conduct electricity and thermal energy
• What is one feature of covalent bonds?

  They have high melting points.
• Describe the structure of graphite in terms of layers of carbon atoms.

  Graphite contains layers of hexagons with each carbon having 3 bonds. The extra electrons become delocalised between the layers.
• Describe the relationship between the graphite and graphene.

  Graphite is made up of many layers of graphene stacked on top of each other, while graphene is just one single layer of carbon atoms.
• List the main physical properties and uses of fullerenes

  Hollow shaped, very strong, hexagonal rings. It can deliver drugs to the body, work as a lubricant and act as a catalyst ( large surface to volume ratio) and in electrons.
• State the molecular formula of buckminsterfullerene

  C^60
• List the physical properties of metals

  solid, hard, malleability, luster, ductility, and conductivity.
• Describe the structure of a pure metal

  layers of positive metal ions surrounded by delocalised electrons
• Explain the properties of diamond in terms of its bonding

  High melting point: every carbon is bonded to four others, the strong covalent bonds require lots of energy to break

  Doesn't conduct electricity as it has no delocalised electrons to carry the charge
• Explain the properties of graphite in terms of its bonding

  High melting point: strong covalent bonds between carbon atoms require lots of

  energy to break

  Soft: weak intermolecular forces between the layers so they can slide over each

  other.

  Conducts electricity/thermal energy: has delocalised electrons which can move

  between layers and carry electrical charge/thermal energy.
• Explain the structure of fullerenes

  All the carbon atoms are equivalent meaning no carbon atoms are stuck on the end of the molecule. Arranged in a sphere
• Describe an ionic lattice

  Every ion is surrounded by multiple ions of the opposite charge, forming a multilayered 3d grid
• Can ionic compunds conduct electricity

  Only when molten or dissolved
• Describe a covalent bond

  Covalent bonds share electrons between atoms

  (ex: H20 or water)
• What is an intermolecular force?

  the force of attraction between molecules
• What factors affect the rate of evaporation

  temperature, surface area, draught
• Why do substances have different melting points?

  The strength of the attractive forces between particles varies in different substances.

  Stronger forces of attraction → higher melting points
• What is a monatomic ion?

  An ion formed by a single atom
• How are double and triple covalent covalent bonds formed

  A double bond is formed when two atoms use two electron pairs to form two covalent bonds; a triple bond results when two atoms share three electron pairs to form three covalent bonds.
• What are the properties of simple covalent bonds?

  Low melting and boiling point- there are only weak intermolecular forces between the molecules which don't need much energy to overcome them forces

  Do not conduct electricity- covalent molecules are not charged and have no free moving electrons.
• Explain the structure of carbon nanotube

  Cylindrical tubes of carbon atoms that are very long compared to their diameter
• Explain the properties of carbon nanotube

  Very strong, light and flexible. Has delocalised electrons so is able to conduct electricity
• What are the uses of carbon nanotube

  Nanotechnology, electronics. (E.g. tennis rackets)
• Describe diamond in terms of its bonding

  In diamond each C is bonded to 4 other carbons in a tetrahedral arrangement
• What are the properties of ionic bonding

  - High melting and boiling points.- takes a lot of energy to overcome the many strong ionic bonds in the lattice. There is a strong electrostatic force between the positive and negative ions in the giant lattice

  - conduct electricity when liquid/ molten- ions are able to move so there is a flow of charged ions (current)

  Do not conduct electricity when solid- ions are in fixed positions so cannot flow
• What is a polymer?

  A polymer is a substance made from very large molecules made up of many repeating units called monomers. They are usually solid because the intermolecular forced are relatively strong.
• Why are alloys harder than pure metals?

  the different sized atoms of the metals distort the layers in the structure, making it more difficult for them to slide over each other
• What is nanoscience?

  the study of small particles between 1-100nm in size
• What are used of nano particles

  Suncream- nano particles are more effective at blocking sun rays- they are smaller than skin cells so can go through the skin into the blood stream. Unpredictable effects on our cells?

  Silver nano particles used in fridges, antimicrobial dressings- inhibit growth of microorganisms (protect against bacteria)- scientists are also worried about nanoparticles entering the environment and affecting aquatic life
• What are the three states of matter?

  solid, liquid, gas