please help with these questions on gold

Answer the following questions in the spaces provided. 1. Identify four physical properties of gold that made it a great choice for currency. (1 mark) 2. Colloidal gold in solution changes colour depending on the size of the particles. Briefly explain how particle size relates to the colours we can see. ( 2 marks) [ 3. Copper and silver are better conductors of electricity than gold, but gold is more commonly used in electronics. Explain why. (1 mark) [ 4. Provide a brief summary of the history of gold mining in New Zealand (3 marks) Choose one important use of gold other than currency and answer the questions below