Question 1: Explain the general structure of a metallic element and how metallic bonds are formed.

Answer: Metals consist of a lattice of positive metal ions surrounded by a 'sea' of delocalised electrons. Metallic bonds are formed by the electrostatic attraction between these positive ions and the delocalised electrons.

Question 1: Define 'delocalised electrons' in the context of metallic bonding.

Answer: Electrons that are not attached to any specific atom and are free to move throughout the metal lattice.

Question 2: Describe how the structure of metals contributes to their ability to conduct electricity.

Answer: The delocalised electrons in the metallic structure are free to move, allowing electric charge to flow through the metal.

Question 1: Calculate the number of delocalised electrons contributed by 1 mole of aluminium atoms, given that each aluminium atom contributes 3 delocalised electrons.

Answer: Number of delocalised electrons = 3 × Avogadro's number (6.022 × 10^23) = 1.807 × 10^24 electrons.

Question 2: If a block of copper contains 8.5 × 10^22 delocalised electrons, how many copper atoms are in the block? (Assume each atom contributes 1 delocalised electron).

Answer: Number of atoms = total electrons / electrons per atom = 8.5 × 10^22 / 1 = 8.5 × 10^22 atoms.

Question 1: Describe a safe procedure to test the electrical conductivity of a metal sample in a classroom setting.

Answer: Connect the metal sample to a battery and a light bulb using wires and clips, ensuring all connections are secure and the power source is switched on briefly to observe if the bulb lights, indicating conductivity. Always ensure the circuit is complete and avoid short circuits.

Question 1: A metal sample has a melting point of 660°C. Explain how the metallic structure contributes to this high melting point.

Answer: The strong electrostatic forces between the metal ions and delocalised electrons require a large amount of energy to break, resulting in a high melting point.

Question 2: A student reports that a particular metal is highly malleable and ductile. Explain how the metallic structure accounts for these properties.

Answer: The layers of positive ions in the metallic lattice can slide over each other without breaking the bonds, due to the 'sea' of delocalised electrons, making the metal malleable and ductile.

Question 1: Describe how the structure of metallic bonds leads to their characteristic properties such as electrical conductivity, malleability, and high melting points. (6 marks)

Answer: The metallic structure consists of positive metal ions arranged in a lattice surrounded by a 'sea' of delocalised electrons. These delocalised electrons enable metals to conduct electricity efficiently, as they are free to move and carry charge. The non-directional nature of metallic bonds allows layers of ions to slide past each other, giving metals their malleability and ductility. Additionally, the strong electrostatic attraction between the ions and the delocalised electrons requires significant energy to break, resulting in high melting points.

Question 1: Explain why aluminium is commonly used in aircraft construction based on its metallic structure and properties.

Answer: Aluminium has a lightweight metallic structure with delocalised electrons, making it strong yet light, corrosion-resistant, and highly conductive, ideal for aircraft construction.