Photo AI
This question is about sodium chloride and iodine - AQA - GCSE Chemistry - Question 6 - 2015 - Paper 2
Question 6
This question is about sodium chloride and iodine. (a) Describe the structure and bonding in sodium chloride. (b) When sodium chloride solution is electrolysed, on... show full transcript
Worked Solution & Example Answer:This question is about sodium chloride and iodine - AQA - GCSE Chemistry - Question 6 - 2015 - Paper 2
Step 1
Describe the structure and bonding in sodium chloride.
Answer
Sodium chloride (NaCl) has a lattice structure, also referred to as a giant ionic structure. The NaCl is composed of sodium ions (Na⁺) and chloride ions (Cl⁻), held together by strong electrostatic attractions between the positively charged sodium ions and the negatively charged chloride ions. This arrangement creates a regular, repeating pattern, forming a solid crystal structure.
Step 2
Step 3
Step 4
Complete Figure 4 to show the bonding in iodine.
Answer
In Figure 4, iodine (I₂) molecules can be represented with two circles, each containing one dot to indicate a bonding pair of electrons. Thus, the diagram should show two circles overlapping, each with one unpaired electron represented by a single dot on the outer edges.
Step 5
Explain why iodine has a low melting point.
Answer
Iodine has a low melting point because it exists as simple molecular structures with weak van der Waals forces between these molecules. These intermolecular forces are relatively easy to overcome, requiring only a small amount of energy to transition from solid to liquid.
Step 6
Explain, in terms of particles, why liquid iodine does not conduct electricity.
Answer
Liquid iodine does not conduct electricity because it consists of neutral iodine molecules (I₂) that do not have free or mobile electrons or ions to carry an electric charge. Therefore, when dissolved or melted, iodine cannot provide the charged particles necessary for electrical conductivity.