Metallic

• Which molecules contain multiple covalent bonds?


  CO2 and H2O2
• Which molecules contain coordinate bonds?


  NH3
• What is a dot and cross diagram of ammonia?


  • Shows nitrogen atom with three bonding pairs and one lone pair of electrons.
  • Bonding pairs are shared between nitrogen and hydrogen atoms.
  • Lone pair is not shared and remains on the nitrogen atom.
• How does a coordinate bond form?


  A coordinate bond forms when one atom donates both electrons to a bond.
• What are the characteristics of metallic bonding?


  • Metals are generally solids with particles packed closely.
  • Outer shell electrons are delocalised and can move between layers.
  • Delocalised electrons allow metals to conduct electricity and heat.
• What is the definition of delocalised electrons in metals?


  Delocalised electrons are electrons that are not confined to any one atom.
• Why can metals conduct electricity?

  Because delocalised electrons can move and carry charge.
• How do metals conduct heat?


  Heat is conducted through the movement of closely packed particles.
• What is an example of a metal that is an excellent conductor of heat?


  Silver
• What are the properties of metals?

  1. Conduct electricity due to delocalised electrons.
  2. Conduct heat through closely packed particles.
  3. Ductile (can be drawn into wires).
  4. Malleable (can be hammered into shape).
  5. High densities due to tightly packed ions.
  6. High melting points due to strong bonding.
• Why are metals ductile and malleable?


  Because the layers in the metallic lattice can slide over each other without disrupting bonding.
• Why do metals have high densities?


  Because positive ions are packed tightly together.
• What is the relationship between melting points and metallic bonding?


  Higher melting points indicate stronger metallic bonds that require more energy to break.
• What are the melting points of sodium, magnesium, and aluminum?


  98°C, 649°C, and 660°C respectively.
• Why does aluminum have a higher melting point than sodium?


  Because aluminum has a stronger metallic bond due to more delocalised electrons.
• What is the melting point of iron?


  1535°C
• What is the melting point of tungsten?


  3410°C
• What is the difference in melting points between transition metals and main group metals?


  • Transition metals have higher melting points than main group metals.
  • This is due to a larger number of d sub-shell electrons that can be delocalised.
• What is the structure of metallic magnesium?


  It consists of a lattice of positive metal ions in a sea of delocalised electrons.
• What is metallic bonding?


  Metallic bonding is the strong electrostatic attraction between a lattice of positively charged metal ions and a sea of delocalized electrons.
• What is the structure of metals?

  • Giant lattice of closely packed positive ions
  • Surrounded by a sea of delocalized electrons
  • Electrons move freely throughout the structure
• Why are metals good conductors of electricity?


  Metals are good conductors of electricity because the delocalized electrons can move freely, carrying charge throughout the structure.
• Why are metals malleable and ductile?


  Metals are malleable and ductile because the layers of metal ions can slide over each other when a force is applied, without breaking the metallic bonds.
• Why do metals have high melting and boiling points?


  Metals have high melting and boiling points because a lot of energy is required to overcome the strong electrostatic attraction between the metal ions and delocalized electrons.
• What is an alloy?


  An alloy is a mixture of a metal with one or more other elements.
• Why are alloys harder than pure metals?


  Alloys are harder than pure metals because the different-sized atoms distort the regular layers in the metal lattice, making it harder for layers to slide over each other.
• What factors affect the strength of metallic bonding?


  The strength of metallic bonding increases with the number of delocalized electrons and the charge on the metal ion.
• How does the melting point of metals change across a period?


  The melting points of metals generally increase across a period as the number of delocalized electrons and the charge on the metal ions increase, leading to stronger metallic bonding.
• Why do metals have high densities?


  Metals have high densities because their atoms are packed closely together in a regular lattice structure.
• What is metal corrosion?


  Metal corrosion is the gradual degradation of metals due to chemical reactions with substances like oxygen and water.
• What is an example of metal corrosion?


  An example of metal corrosion is rusting, where iron reacts with oxygen and water to form iron(III) oxide.
• What are delocalized electrons in the context of metallic bonding?


  Delocalized electrons are the electrons in a metal that are not bound to any particular atom and can move freely throughout the structure.
• What is meant by a "giant metallic lattice"?


  A giant metallic lattice refers to the regular, repeating arrangement of metal cations surrounded by a sea of delocalized electrons, extending throughout the material.
• What properties of metals are due to the presence of delocalized electrons?


  Delocalized electrons give metals their high electrical conductivity, thermal conductivity, and the ability to reflect light, making them shiny.
• Why are metals good conductors of heat?

  Metals conduct heat well because the delocalized electrons transfer kinetic energy rapidly through the lattice when heated.
• How do the melting points of Group 1 metals compare to other metals?


  Group 1 metals have relatively low melting points compared to other metals because they have fewer delocalized electrons and weaker metallic bonds.
• Why are alkali metals (Group 1) more reactive than most other metals?


  Alkali metals are more reactive because they have only one electron in their outer shell, which is easily lost, forming a positive ion.
• How does metallic bonding differ in transition metals compared to Group 1 metals?


  Transition metals have stronger metallic bonds than Group 1 metals because they have more delocalized electrons and smaller atomic radii, leading to stronger electrostatic attractions.
• Why are transition metals often used as catalysts?


  Transition metals are used as catalysts because they can adsorb reactants onto their surface and provide a pathway with a lower activation energy for reactions.
• What is superconductivity?


  Superconductivity is a phenomenon where a material loses all electrical resistance at very low temperatures.