Metallic bonding

• What is metallic bonding?

  Metallic bonding is the attraction between positively charged metal ions and delocalised electrons.

  
• How are metal atoms arranged in metallic bonding?

  Metal atoms are tightly packed together in lattice structures.
• What happens to the electrons in metallic bonding?

  The electrons in their outer shells are free to move throughout the structure.

  
• What are the free-moving electrons in metallic bonding called?

  They are called 'delocalised' electrons.

  
• What occurs when electrons are delocalised in metallic bonding?

  The metal atoms become positively charged.

  
• What keeps the lattice structure of metals in place?

  The positive charges repel each other and maintain the lattice structure.
• What are the electrostatic forces in metallic bonding?

  They are the forces between the positive metal centres and the delocalised electrons.

  
• What are the properties of metals?

  • Malleability
  • Strength
  • Electrical conductivity
  • Thermal conductivity
  • High melting and boiling points
• What does malleability in metals refer to?

  Malleability refers to the ability of metallic compounds to be shaped or deformed without breaking.
• How do metallic layers behave when a force is applied?

  The metal layers can slide over each other without breaking the lattice structure.

  
• Why are metallic compounds strong and hard?

  They are strong and hard due to the strong attractive forces between the metal ions and delocalised electrons.

  
• Can metals conduct electricity in solid and liquid states?

  Yes, metals can conduct electricity in both solid and liquid states.
• What happens to delocalised electrons when a potential difference is applied?

  They repel away from the negative terminal and move towards the positive terminal.

  
• How does the number of outer electrons affect electrical conductivity across a period?

  As the number of outer electrons increases, the ability to conduct electricity also increases.
• How many outer electrons does sodium have?

  Sodium has 1 outer electron.
• How many outer electrons does magnesium have?

  Magnesium has 2 outer electrons.
• How many outer electrons does aluminium have?

  Aluminium has 3 outer electrons.
• Why are metals good thermal conductors?

  Metals are good thermal conductors due to the behaviour of their cations and delocalised electrons.
• What happens to cations in a metal lattice when heated?

  The cations vibrate more vigorously as their thermal energy increases.
• How do vibrating cations contribute to thermal conductivity?

  They transfer their kinetic energy as they collide with neighbouring cations, conducting heat.
• What role do delocalised electrons play in thermal conductivity?

  Delocalised electrons carry increased kinetic energy and transfer it rapidly throughout the metal.

  
• Why do metals have high melting and boiling points?

  They have high melting and boiling points due to strong electrostatic forces of attraction in the metallic lattice.
• How does the number of mobile charges affect melting and boiling points across a period?

  As the number of mobile charges increases, the melting and boiling points also increase.
• What properties should be considered when choosing a metal for a specific job?

  • Malleability / ductility
  • Electrical conductivity
  • Thermal conductivity
  • Melting / boiling point
  • Strength
  • Strength-to-weight ratio
  • Density
  • Toxicity
  • Corrosion resistance
  • Reactivity
  • Lustre
  • Sonority
• Why is aluminium used in food cans?

  Because it is non-toxic and resistant to corrosion and acidic food substances.
• Why is copper used in electrical wiring?

  Because it is a good electrical conductor and malleable/ductile.
• Why is stainless steel used for cutlery?

  Because it is strong and resistant to corrosion.
• What factors affect the strength of metallic bonds?

  The charge on the metal ion and the size of the metal ion affect the strength of metallic bonds.
• How does the charge on the metal ion affect metallic bond strength?

  A greater charge on the metal ion leads to a stronger electrostatic attraction and a stronger metallic bond.
• What is the relationship between ionic radius and metallic bond strength?

  Metal ions with smaller ionic radii exert a greater attraction on delocalised electrons, leading to stronger metallic bonds.

  
• How does the melting point of metals change across a period?

  The melting point of metals increases moving across a period from left to right.
• How does the melting point of metals change down a group?

  The melting point of metals decreases moving down a group.
• What is one factor that can influence melting points besides metallic bonding?

  The metal packing structure can also influence the melting point.
• What should students remember about trends in melting points?

  Students should remember that trends are not rules and other factors can cause subtle differences.