2-Bonding, Structure and the Properties of Matter

• Coarse particles (PM10)


  Diameters between 1 x 10-5 m and 2.5 x 10-6 m, often referred to as dust
• Conductor


  A material which contains charged particles which are free to move to carry electrical or thermal energy
• Covalent bond


  A shared pair of electrons between two non-metals
• Diamond


  A giant covalent structure which is made up of carbon atoms each of which form four covalent bonds with four other carbon atoms
• Electrostatic forces


  The strong forces of attraction between oppositely charged ions
• Empirical formula


  The smallest whole number ratio of atoms of each element in a compound
• Fine particles (PM2.5)


  Diameters between 100 and 2500 nm (1 x 10-7 m and 2.5 x 10-6 m)
• Fullerenes


  Molecules of carbon atoms with hollow shapes, based on hexagonal rings of carbon atoms but may also contain rings with five or seven carbon atoms
• Gas


  The state of matter where the particles have the most energy, are relatively spread out and move randomly in all directions
• Graphene


  A single layer of graphite with properties that make it useful in electronics and composites
• Graphite


  A giant covalent structure which is made up of carbon atoms each of which form three covalent bonds with three other carbon atoms, forming layers of hexagonal rings which have no covalent bonds between the layers
• Ion


  An atom or molecule with an electric charge due to the loss or gain of electrons
• Ionic bond


  A metal atom loses electron(s) to form a positively charged ion and a non-metal gains these electron(s) to form a negatively charged ion, forming an ionic bond between the oppositely charged ions
• Ionic compound


  Chemical compound formed of ions, held together by strong electrostatic forces
• Intermolecular forces


  The forces which exist between molecules, the strength of which impact physical properties like boiling/melting point
• Lattice


  A repeating regular arrangement of atoms/ions/molecules, occurring in crystal structures
• Liquid


  The state of matter where the particles are arranged randomly and close together and are able to move past each other
• Metallic bond


  The bonds present in metals between the positive metal ions and negatively charged electrons
• Metals


  Elements that react to form positive ions, found to the left and towards the bottom of the periodic table
• Molecular formula

  The actual ratio of atoms of each element present in a compound
• Nanoparticles

  Particles with diameters between 1 nm to 100 nm in size, which can exhibit properties different to those for the same material in bulk
• Nanoscience

  The study of structures that are 1–100 nm in size, of the order of a few hundred atoms
• Non-metals


  Elements that react to form negative ions, found towards the right and top of the periodic table
• Particle theory


  The theory which models the three states of matter by representing the particles as small solid spheres, helping to explain melting, boiling, freezing and condensing
• Polymers


  Large long-chain molecules made up of lots of small monomers joined together by covalent bonds
• Repeat unit


  The part of a polymer whose repetition would produce the complete polymer chain
• Solid


  The state of matter where the particles hold a regular arrangement and have the least amount of energy
• State symbols


  The symbols used in chemical equations to denote the states of the chemicals reacting: (s) - solid, (l) - liquid, (g) - gas, (aq) - aqueous solution