Question 1: Define a metal and a non-metal based on their atomic properties and position in the periodic table.

Answer: A metal is an element that is typically a good conductor of electricity and heat, malleable, and usually solid at room temperature, found on the left side of the periodic table. A non-metal is an element that is generally a poor conductor, brittle in solid form, and found on the right side of the periodic table.

Question 2: Explain how atomic structure differences between metals and non-metals influence their properties at the nanoscale.

Answer: Metals have a lattice of delocalised electrons which allow for conductivity and malleability, whereas non-metals have more localized electrons leading to insulative and brittle properties. At the nanoscale, these differences affect how materials can be manipulated for applications like nanowires (metals) or insulating coatings (non-metals).

Question 3: Identify two properties of metals and two properties of non-metals that are important in nanotechnology applications.

Answer: Metals: high electrical conductivity, ductility; Non-metals: electrical insulation, brittleness.

Question 1: Calculate the number of protons, neutrons, and electrons in a neutral atom of aluminium-27 (Atomic number = 13). Show your working.

Answer: Protons = 13; Electrons = 13; Neutrons = 14 (27 - 13).

Question 2: A nanoparticle of sulphur (Atomic number 16, Atomic mass 32 u) contains 16 atoms. Calculate the total number of protons in the nanoparticle.

Answer: Total protons = 16 atoms × 16 protons = 256 protons.

Question 1: Describe a theoretical experiment to investigate the conductivity of metal nanoparticles compared to bulk metals. Include variables to be controlled.

Answer: The experiment would involve measuring electrical resistance of metal nanoparticles and bulk metal samples under identical conditions. Variables include temperature, sample size, and environmental factors. The aim is to compare how size reduction affects conductivity due to surface effects and electron behaviour.

Question 2: List two safety precautions necessary when handling nanomaterials in a laboratory setting.

Answer: Wearing appropriate personal protective equipment (PPE) such as gloves and masks; working in well-ventilated areas or fume hoods to prevent inhalation of nanoparticles.

Question 1: A company uses metallic nanoparticles of silver for antibacterial coatings. Explain how the atomic properties of silver contribute to its effectiveness at the nanoscale.

Answer: Silver atoms have a high surface area to volume ratio at the nanoscale, increasing their contact with bacteria. The delocalised electrons in metallic silver facilitate electrical interactions that disrupt bacterial cell functions, making them effective antimicrobials.

Question 2: Discuss one advantage and one potential risk of using metal nanoparticles in consumer products.

Answer: Advantage: Enhanced properties such as improved conductivity, antibacterial effects, or strength due to nanoscale size. Risk: Potential toxicity if nanoparticles are released into the environment or ingested, possibly affecting human health and ecosystems.