Module 3 Model Questions And Answers

Module 3 Model Questions And Answers State one benefit of adding chlorine to water (1) - Answer-Kills germs Suggest one possible hazard of adding chlorine to drinking water (1) - Answer-It is toxic Explain the decrease in the atomic radii across the period from Na to Cl (3) - Answer-1) nuclear charge increases 2) electron shielding remains the same 3) greater attraction to nucleus Describe and explain the trend, down the group, in the reactivity of the Group 2 elements with water (5) - Answer-1) reactivity decreases down the group 2) atomic radii increases as there are more shells 3) there is more electron shielding 4) nuclear attraction decreases 5) ionisation energy decreases so it is easier to remove an outer electron Explain why xenon has a lower first ionisation energy than neon (3) - Answer-1) Xenon has a bigger atomic radius 2) Xenon has more shielding 3) Nuclear attraction decreases What term is used to describe a redox reaction in which an element is both oxidised and reduced? (1) - Answer-Disproportionation Why does the modern Periodic Table not arrange some elements in order of increasing atomic mass? (1) - Answer-They are arranged in increasing atomic number Describe what you would expect to see when magnesium ribbon is added to an excess of dilute hydrochloric acid (2) - Answer-1) Bubbles 2) Magnesium dissolves Why is the first ionisation energy of strontium larger than the first ionisation energy of rubidium? (3) - Answer-1) Strontium has one more proton so has a greater nuclear charge 2) The atomic radius of strontium is smaller 3) This means the outer electrons are attracted more strongly to the nucleus Why is the second ionisation energy of rubidium larger than the second ionisation energy of strontium? (2) - Answer-1) The second ionisation energy of rubidium involves removing an electron from a shell closer to the nucleus 2) Therefore, rubidium experiences more attraction to the nucleus Continues...