Chemistry As Level OCR | 52 Questions and Answers with complete solution

Atomic Radius, Nuclear Charge, Electron Shielding - What are the 3 things that affect first ionisation energy? Increase. More protons- stronger attraction. Not much extra shielding. - What is the general trend in ionisation energy across periods? And why? Decrease due to increased attraction between electrons and nucleus. - What is the trend in atomic radius across a period? Increase due to metallic bonds getting stronger. - What is the trend in boiling points across metals? Silicon. Strong covalent bonds. - Which element in period 3 has the highest melting point? And why? Greater Van der Waals forces. - What do more atoms in a molecule mean for Van der Waals forces? The noble gases. They are individual atoms. - Which elements have the lowest melting and boiling point? And why? Simple molecular structure. - What bonding structure does phosphorus have? 2+ ions. - What ions do Group 2 elements form? Increase. The lower the first and second ionisation energies, the more reactive the element. - What is the trend in reactivity down Group 2? And why? Decrease. (Increased atomic radius, and the shielding effect) - What is the trend in ionisation energies down Group 2?Hydroxides. - What do Group 2 elements produce when they react with water? green, orange, brown - What are the colours of the halogens chlorine, bromine, and iodine? in order of question. Decreases. - What is the trend in reactivity of halogens down the group? Oxidising agents. They gain an electron in their outer shell, so they are reduced. This means that they oxidise other substances. - Are halogens oxidising or reducing agents? And why? Add silver nitrate. - Which test can be done to check for halide ions? Chlorine is white, Bromine is cream, Iodine is yellow. - What are the colours of the precipitates formed when chlorine, bromine, or iodine is present in the silver nitrate test?