Question 1: Define metallic bonding and describe its key features.

Answer: Metallic bonding is the electrostatic attraction between a lattice of metal cations and a 'sea' of delocalised electrons. Its key features include conductivity, malleability, ductility, and a high melting point.

Question 2: Explain why metals are good conductors of electricity based on their structure.

Answer: Metals conduct electricity because their delocalised electrons are free to move throughout the metallic structure, allowing charge to flow.

Question 1: Calculate the number of delocalised electrons per atom in aluminium, given that aluminium has 3 valence electrons.

Answer: 3 electrons per atom

Question 2: If the atomic radius of copper is approximately 128 pm, estimate the density of copper given that its atomic mass is 63.55 g/mol and its lattice contains 1 atom per unit cell. (Use Avogadro's number: 6.022×10²³ mol⁻¹).

Answer: Density ≈ 8.96 g/cm³ (show detailed working in notes)

Question 1: List the variables you would control and the safety precautions necessary for this experiment.

Answer: Controlled variables include temperature, length and thickness of the metal wire. Safety precautions involve wearing safety goggles, handling electrical equipment carefully, and ensuring the circuit is correctly connected to prevent short circuits or electric shocks.

Question 1: A metal with a high melting point also exhibits high hardness and malleability. Explain how this relates to its metallic structure.

Answer: A high melting point indicates strong metallic bonds due to a dense and regular lattice of cations with delocalised electrons, which also contribute to hardness and malleability by allowing layers to slide without breaking the structure.

Question 2: Given data: Metal A has a melting point of 1500°C and Metal B melts at 500°C. Based on their structures, which metal likely has a stronger metallic bond and why?

Answer: Metal A likely has a stronger metallic bond because its higher melting point indicates more energy is required to break the bonds in its metallic lattice.

Question 1: Describe how the sea of delocalised electrons in metallic bonds contributes to the malleability of metals.

Answer: The sea of delocalised electrons allows metal layers to slide past each other when force is applied, without breaking the bonds, which makes metals malleable.

Question 2: Explain why metals generally have high electrical and thermal conductivity based on their structure.

Answer: Because the delocalised electrons are free to move throughout the metallic lattice, they carry charge and heat efficiently, resulting in high electrical and thermal conductivity.

Question 1: Describe how the structure of aluminium makes it suitable for use in aircraft construction.

Answer: Aluminium's metallic structure provides a lightweight yet strong material with good conductivity and corrosion resistance, making it ideal for aircraft frameworks.

Question 2: Identify a technological application that relies on the delocalised electrons in metals and explain its function.

Answer: Electrical wiring uses metals like copper because its delocalised electrons allow efficient conduction of electricity, enabling current flow in circuits.