Bonding, structure & properties of matters

• ionic bonding the particles are oppositely charged ions
• covalent bonding the particles are atoms in which share pairs of electrons
• metallic bonding particles are atoms in which share the delocalised electrons
• ionic bonding - occurs in compounds formed from metals combined with nonmetals
• covalent bonding - occurs in most nonmetals elements & non-metal compounds
• metallic bonding - occurs in metallic elements & alloys
• When a metal atom reacts with a non-metal atom electrons in the atom of the metal are transferred to the non-metal
• Metal atom loses electrons to become positively charged ions
• Nonmetals atoms gain electrons to become negatively charged ions
• Ionic compounds our house together by strong electrostatic forces of attraction between opposite charged irons
• an ionic compound is a giant structure of irons
• limitations of using dot & crosses to represent a giant ionic structure

  • dot & crosses only show a few atoms when they actually form a giant ionic lattice which contains a large number of atoms
• limitations of using ball & stick to represent a giant ionic structure

  • ball & stick the ions are not joined by sticks / physical bonds and has gaps
• limitations of using two dimensional diagrams to represent a giant ionic structure

  • giant ionic lattice are 3D so the 2D diagrams only showes one layer of it
• limitations of using three dimensional diagrams to represent a giant ionic structure

  • three dimensional diagrams may not be able to show all the ions in a large structure
  • it is difficult to draw and does not show electrons
• covalent bonding can be represented in small molecules, polymers, giant covalent structures or using a line to represent a single bond
• limitations of using dot & crosses to represent molecules or giant covalent structures

  • dot & crosses come easily be used to show the bonding in simple molecules but not giant covalent structures as there are too many atoms
• limitations of using balls & sticks to represent molecules or giant covalent structures

  • ball & sticks - in covalent structures the atoms at the edge haven’t got the correct number of bonds
• limitations of using two dimensional diagrams to represent molecules or giant covalent structures

  • two dimensional diagrams don’t show the shape of the molecule
• limitations of using three dimensional diagrams to represent molecules or giant covalent structures

  • three dimensional diagrams often only show a small portion of the giant covalent structure
• metallic bonding - the electrons in the outer shell of metal atoms are delocalised & so free to move through the whole structure
• why alloys are harder than pure metals

  • the atoms In alloys are different sizes
  • which means the layers of atoms are distorted
  • therefore layers slide over each other less easily
• Metals are good conductors of electricity because the dealer electrons in the metal carry electrical charge through the metal
• Metlas are good conductors of thermal energy because energy is transferred by the delocalised electrons
• properties of ionic bonding

  • high boiling & melting point because of the large amount of energy needed to break the many strong bonds
• alloy - a mixture of metals
• The amount of energy needed to change state from solid to liquid & liquid to gas depends on the strength of the forces between the particles
• limitation of the particle theory in relation to changes of state from solid to liquid

  In the model, there are no forces, that all the particles are represented as spheres & the spheres are solids
• The stronger the forces between particles, the higher the boiling & melting point of the substance
• aq- dissolved in water
• Small molecules are usually gases or liquids that have low boiling & melting point
• these intermolecule substances do not conduct electricity because the molecules do not have an overall electric charge
• Why intermolecular forces are weak compared with covalent bonds

  • intermolecular forces are weaker as they are smaller in size & have lower boiling & melting points
  • covalent bonds are bigger in size and very strong
• properties of diamond

  • very hard
  • high melting point
  • does not conduct electricity contains 4 hexagons of carbon
• limitations of using three - dimensional diagrams to represent giant ionic compounds

  • May not be able to share all the ions in a large structure
  • can be difficult & time consuming to draw
  • dont show all electrons
• solid, liquid & gas

  • the amount of energy needed to change state from solid to liquid & from liquid to gas depends on the strength of the forces between the particles
  • the stronger the forces between the particles the higher the boiling & melting point of a substance
• limitations of simple model in three states of matter matter

  • limitations of the simple models is that in the model there are not forces, that all particles are represented as spheres & tha the spheres are solid
• predicting the state of a substance

  • below the melting point a substance is solid
  • above the boiling point its a gas
  • between the two points, its a liquid
• properties of graphite

  • layered structures of hexagonal rings
  • good conductor of heat & electricity due to its delocalised electrons, so is used in electronics & composite materials
• properties of fullereness

  • molecules with hollow shapes such as spheres or tubes
  • rings of carbon atoms
  • good conductors of heat electricity as has delocalosed electrons