AQA GCSE Chemistry – Electrolysis Verified Solution

AQA GCSE Chemistry – Electrolysis Verified Solution 1. What is the systematic organization of elements in the periodic table called? Answer: The periodic table is a systematic organization of elements, known as the periodic table, due to its regularly repeating patterns. 2. Who was the scientist who proposed one of the first periodic tables? Answer: John Dalton proposed one of the first periodic tables, organizing elements in order of atomic weight. 3. Who built upon Dalton's ideas and arranged elements into sets of eight? Answer: John Newlands built upon Dalton's ideas and arranged elements into sets of eight, noting that each eighth element had similar properties. 4. Who is credited with proposing the modern periodic table? Answer: Dmitri Mendeleev proposed the modern periodic table, leaving gaps for undiscovered elements and receiving acceptance from the scientific community. 5. What determines an element's position on the periodic table? Answer: An element's atomic number, which is equal to the number of protons in its nucleus, determines its position on the periodic table. 6. What is a group in the periodic table? Answer: A group is a column in the periodic table, and its number equals the number of electrons in an element's outer shell. 7. What is a period in the periodic table? Answer: A period is a row in the periodic table. 8. Which elements are found to the left of the periodic table? Answer: Metals are found to the left of the periodic table and are electrical conductors. 9. Which elements are found in the top right-hand corner of the periodic table? Answer: Non-metals are found in the top right-hand corner of the periodic table and are electrical insulators. 10. What are the noble gases? Answer: The noble gases are group 0 of the periodic table. 11. Which elements are part of group 1 of the periodic table? Answer: Alkali metals are part of group 1 of the periodic table. 12. What trends can be observed when moving down group 1 and 7? Answer: When moving down group 1 and 7, reactivity decreases due to increasing distance from the nucleus, occupied energy levels, and size of positive charge on the nucleus. 13. Why do transition metals have higher melting points and densities compared to alkali metals? Answer: Transition metals have higher melting points and densities due to their stronger bonds and multiple energy levels. 14. Why do noble gases have full electron shells? Answer: Noble gases have full electron shells, making them unreactive due to their completed outer energy level. 15. What is formed when an alkali metal reacts with water? Answer: Metal hydroxide and hydrogen are formed when an alkali metal reacts with water. 16. Describe the reaction between lithium and water. Answer: Lithium reacts with water by floating, fizzing steadily until it disappears. 17. Describe the reaction between sodium and water. Answer: Sodium reacts with water by melting to form a ball, fizzing rapidly, and possibly producing an orange flame. 18. Describe the reaction between potassium and water. Answer: Potassium reacts with water by fizzing rapidly, setting on fire with a purple flame, and sometimes producing a 'pop' at the end of the reaction. Why can ionic compounds only conduct electricity when molten or in a solution ️an ionic compound in solid state forms a lattice so the ions aren't free to move around. when they are dissolved or melted the ions separate and are free to carry electrical currents What does aqueous mean? ️dissolved in water Which two ions could be discharged at the cathode from an aqueous solution ? ️H+ or cation from ionic compound Which two ions could be discharged at the anode from an aqueous solution ? ️OH- or anion from ionic compound Why is there a choice of two ions at each electrode to be discharged in an aqueous solutions? ️In water a small fraction of the molecules break down into H+ and OH- ions What is the rule for which anion will be discharged at the anode from an aqueous solution? ️O2 is produced from the discharge of OH- unless the ionic compound contains halide ions, in this case the halogen is produced E.g. 4OH- —> 2H2O+ O2+4e- What is the rule for which cation will be discharged at the cathode from an aqueous solution? ️Hydrogen produced from the discharge of H+ if ionic compound contains metal ions more reactive than hydrogen E.g. 2H+ +2e- —> H2 Test for hydrogen gas ️Lit wooden splint Burns with a Squeaky pop Test for chlorine gas ️Bleaches damp litmus paper Test for oxygen gas ️Relights a glowing splint