# GCSE Chemistry Paper 1: Atomic Structure, Periodic Table, Bonding, Structure & Quantitative Chemistry (Moles) > Complete GCSE/IGCSE Chemistry Paper 1 coverage: subatomic particles, history of the atomic model, Group 1 & Group 7 reactivity trends, ionic/covalent/metallic bonding, giant covalent allotropes, mole calculations, atom economy, titrations, electrolysis, and energy profile diagrams. - **Canonical URL:** https://flashcards.world/flashcards/sets/42943c60-ddfc-4a15-a136-075f70e4584d/ - **Markdown URL:** https://flashcards.world/flashcards/sets/42943c60-ddfc-4a15-a136-075f70e4584d.md - **Level:** basic - **Languages:** en → en - **Total Cards:** 32 ## Flashcards (32 Cards) | # | Front (Term / Prompt) | Back (Definition / Answer) | Example | Multiple-Choice Options | | :--- | :--- | :--- | :--- | :--- | | 1 | Compare exothermic and endothermic reactions in terms of energy transfer, temperature change of surroundings, and reaction profile diagrams. | Exothermic (combustion, neutralisation, respiration): transfers thermal energy to the surroundings, so temperature of surroundings increases; products have lower energy than reactants (negative ΔH). Endothermic (thermal decomposition, citric acid + sodium hydrogencarbonate): absorbs energy from surroundings, so temperature decreases; products have higher energy than reactants (positive ΔH). | | | | 2 | What is the GCSE Reactivity Series of metals (including Carbon and Hydrogen) from most reactive to least reactive? | Potassium (K) > Sodium (Na) > Lithium (Li) > Calcium (Ca) > Magnesium (Mg) > Aluminium (Al) > [Carbon (C)] > Zinc (Zn) > Iron (Fe) > Tin (Sn) > Lead (Pb) > [Hydrogen (H)] > Copper (Cu) > Silver (Ag) > Gold (Au) > Platinum (Pt). | | | | 3 | State the relative mass and relative charge of a proton, neutron, and electron. | Proton: relative mass = 1, relative charge = +1. Neutron: relative mass = 1, relative charge = 0. Electron: relative mass ≈ 0 (or 1/1836), relative charge = -1. | | | | 4 | What are the general word equations for an acid reacting with: (1) metal, (2) metal oxide/hydroxide, and (3) metal carbonate? | 1) Acid + Metal → Salt + Hydrogen; 2) Acid + Metal Oxide/Hydroxide → Salt + Water; 3) Acid + Metal Carbonate → Salt + Water + Carbon Dioxide. (HCl forms chloride salts, H2SO4 forms sulfate salts, HNO3 forms nitrate salts). | | | | 5 | Why do simple molecular substances (e.g., CO2, H2O, CH4) have low melting and boiling points? | Although the covalent bonds between atoms within each molecule are very strong, the intermolecular forces between separate molecules are weak. Only a small amount of energy is needed to overcome these weak intermolecular forces during melting or boiling (covalent bonds are NOT broken). | | | | 6 | How does a simple chemical cell work, and how does the voltage depend on the metals used as electrodes? | A chemical cell consists of two different metals in contact with an electrolyte; the more reactive metal oxidises (loses electrons) and pushes electrons through the external wire to the less reactive metal. The greater the difference in reactivity between the two metal electrodes, the higher the cell voltage. | | | | 7 | Why is cryolite used in the industrial extraction of aluminium by electrolysis of aluminium oxide (Al2O3), and why must the carbon anodes be replaced regularly? | Aluminium oxide is dissolved in molten cryolite to lower the operating melting temperature from ~2050°C to ~900°C, reducing energy costs. At the positive carbon anodes, oxide ions are oxidised to oxygen gas (2O²⁻ → O2 + 4e⁻), which reacts with the hot carbon anodes to form CO2 gas, burning them away. | | | | 8 | In the electrolysis of molten lead(II) bromide (PbBr2), what happens at the cathode (negative electrode) and anode (positive electrode)? | At the negative cathode: Pb²⁺ ions are attracted and reduced by gaining electrons to form molten lead metal: Pb²⁺ + 2e⁻ → Pb. At the positive anode: Br⁻ ions are attracted and oxidised by losing electrons to form brown bromine gas: 2Br⁻ → Br2 + 2e⁻. | | | | 9 | How do ionic bonds form between metals and non-metals, and what is the structure of solid sodium chloride (NaCl)? | Metal atoms lose outer shell electrons to form positive cations (Na⁺), and non-metal atoms gain electrons to form negative anions (Cl⁻). They are held together in a giant ionic lattice by strong electrostatic forces of attraction acting in all directions between oppositely charged ions. | | | | 10 | What are the half-equations and overall reaction in a hydrogen-oxygen fuel cell, and what is its main environmental advantage? | Hydrogen is oxidised at the anode (2H2 → 4H⁺ + 4e⁻ or 2H2 + 4OH⁻ → 4H2O + 4e⁻) and oxygen is reduced at the cathode (O2 + 4H⁺ + 4e⁻ → 2H2O), giving the overall reaction 2H2 + O2 → 2H2O. The only chemical product is pure water, producing zero greenhouse gases at the point of use. | | | | 11 | State the two equations for solution concentration (in g/dm³ and mol/dm³) and how to convert cm³ to dm³. | Concentration (g/dm³) = Mass (g) ÷ Volume (dm³); Concentration (mol/dm³) = Moles (mol) ÷ Volume (dm³). To convert cm³ to dm³, divide by 1,000 (Volume in dm³ = Volume in cm³ ÷ 1,000). Also, Concentration in g/dm³ = Concentration in mol/dm³ × Mr. | | | | 12 | Summarize the discoveries of Thomson, Rutherford, Bohr, and Chadwick in the development of the atomic model. | Thomson: discovered the electron and proposed the 'plum pudding' model (ball of positive charge with embedded electrons). Rutherford: alpha particle scattering experiment showed mass and positive charge are concentrated in a tiny central nucleus. Bohr: electrons orbit the nucleus at fixed energy levels/shells. Chadwick: discovered the neutron in the nucleus. | | | | 13 | How do you calculate the overall energy change (ΔH) of a reaction from bond energies, and why is bond breaking endothermic? | Energy must be supplied to break existing chemical bonds (endothermic, +), whereas energy is released when new chemical bonds form (exothermic, -). Overall Energy Change (ΔH) = Σ(Energy needed to break bonds in reactants) − Σ(Energy released forming bonds in products). | | | | 14 | Why do giant ionic compounds have high melting points and conduct electricity only when molten or in aqueous solution? | High melting points: large amounts of thermal energy are needed to overcome the strong electrostatic forces of attraction between oppositely charged ions in the giant lattice. Electrical conductivity: when solid, ions are fixed in position; when molten or dissolved in water, the ions are free to move and carry charge. | | | | 15 | Describe the step-by-step method for performing an acid-alkali titration (GCSE Required Practical). | 1) Use a volumetric pipette and safety filler to transfer 25.0 cm³ of alkali into a conical flask; 2) Add a few drops of a single-change indicator (phenolphthalein or methyl orange, NOT universal indicator); 3) Fill a burette with acid and record the initial meniscus reading; 4) Add acid while swirling on a white tile, adding drop-by-drop near the endpoint until a permanent colour change occurs; 5) Repeat until concordant titres (within 0.10 cm³) are obtained. | | | | 16 | How does a metal's position relative to Carbon in the reactivity series determine how it is extracted from its ore? | Metals less reactive than carbon (e.g., Zn, Fe, Cu) are extracted by reduction (heating their metal oxide ore with carbon/coke, which displaces the metal). Metals more reactive than carbon (e.g., K, Na, Ca, Mg, Al) cannot be reduced by carbon and must be extracted by electrolysis of the molten compound. | | | | 17 | What are graphene and fullerenes (e.g., Buckminsterfullerene C60 and carbon nanotubes), and what are their key properties? | Graphene is a single layer of graphite (one atom thick) with exceptional tensile strength and electrical/thermal conductivity. Fullerenes are hollow molecules of carbon atoms arranged in hexagons/pentagons (e.g., C60 spheres used for drug delivery/lubricants; nanotubes have high length-to-diameter ratios and conduct electricity). | | | | 18 | Describe metallic bonding and explain why pure metals are malleable whereas alloys are harder. | Metallic bonding is the strong electrostatic attraction between a regular giant lattice of positive metal ions and a 'sea' of delocalised outer-shell electrons. In pure metals, uniform layers of identical atoms slide easily over each other. In alloys, different-sized atoms distort the regular layers, making it harder for layers to slide. | | | | 19 | Why did Mendeleev leave gaps in his early Periodic Table and sometimes reverse the order of atomic weights? | He left gaps for undiscovered elements so that elements with similar chemical properties stayed in the same vertical group, and predicted the properties of missing elements (like gallium/germanium). He reversed pairs (like Te and I) to match group chemical properties, later explained by atomic number (proton number) and isotopes. | | | | 20 | Explain why reactivity decreases down Group 7 (Halogens: F2, Cl2, Br2, I2) and how melting/boiling points change. | Going down Group 7, atomic radius and shielding increase, so the electrostatic attraction between the nucleus and an incoming electron decreases, making it harder to gain 1 electron into the outer shell. Melting and boiling points increase down Group 7 because relative molecular mass increases, leading to stronger intermolecular forces. | | | | 21 | How do you prepare pure, dry crystals of copper(II) sulfate from insoluble copper(II) oxide and dilute sulfuric acid (GCSE Required Practical)? | 1) Gently warm dilute H2SO4 in a beaker; 2) Add insoluble CuO powder in excess while stirring until no more reacts (ensuring all acid is neutralised); 3) Filter the mixture to remove unreacted excess CuO; 4) Heat the blue CuSO4 filtrate in an evaporating basin over a water bath until crystallisation point, leave to cool/crystallise, filter, and pat dry between filter papers. | | | | 22 | State the equations connecting moles (n), mass (m), relative formula mass (Mr), and Avogadro's constant. | Moles (mol) = Mass (g) ÷ Relative Formula Mass (Mr). Number of particles = Moles × Avogadro's constant (6.02 × 10²³ mol⁻¹). | | | | 23 | Explain why reactivity increases down Group 1 (Alkali Metals: Li, Na, K) in 4 mark-scheme points. | 1) Going down Group 1, atoms have more electron shells, so atomic radius increases; 2) The single outer shell electron is further from the positively charged nucleus and experiences greater inner-shell electron shielding; 3) Electrostatic attraction between the nucleus and outer electron decreases; 4) Therefore, the outer electron is lost more easily. | | | | 24 | What volume does 1 mole of any gas occupy at room temperature and pressure (RTP: 20°C and 1 atm)? | 24 dm³ (or 24,000 cm³). Therefore, Volume of gas (dm³) = Moles (mol) × 24. | | | | 25 | What are the equations for Percentage Yield and Atom Economy in GCSE Chemistry? | Percentage Yield = (Actual mass of product obtained ÷ Maximum theoretical mass of product) × 100%. Atom Economy = (Mr of desired product ÷ Sum of Mr of all reactants in balanced equation) × 100%. | | | | 26 | How do you identify the limiting reactant in a chemical reaction and why does it control the product yield? | Convert the masses of all reactants into moles using n = m / Mr and compare them using the stoichiometric ratio from the balanced equation. The limiting reactant is completely used up first; once it runs out, the reaction stops, so the maximum theoretical moles of product are directly proportional to the moles of limiting reactant. | | | | 27 | Define isotopes and explain why isotopes of the same element have identical chemical properties. | Isotopes are atoms of the same element with the same number of protons (atomic number) but different numbers of neutrons (different mass numbers). They have identical chemical properties because they have the same number of electrons in their outer shell. | | | | 28 | How do you calculate Relative Atomic Mass (Ar) from isotopic abundances? Calculate Ar for Chlorine (75% Cl-35 and 25% Cl-37). | Ar = Σ(isotope mass × percentage abundance) ÷ 100. For Chlorine: Ar = [(35 × 75) + (37 × 25)] ÷ 100 = (2625 + 925) ÷ 100 = 35.5. | | | | 29 | Explain the difference between a 'strong vs weak' acid and a 'concentrated vs dilute' acid, and how pH relates to H⁺ concentration. | Strong acids (HCl, H2SO4, HNO3) completely ionise/dissociate in water; weak acids (ethanoic, citric, carbonic acid) only partially ionise in reversible reactions. Concentration refers to total moles of acid per dm³ of solution. Every decrease of 1 on the pH scale represents a 10× increase in H⁺ ion concentration. | | | | 30 | Compare the bonding, structure, hardness, and electrical conductivity of Diamond and Graphite. | Both are giant covalent allotropes of carbon. Diamond: each C atom forms 4 strong covalent bonds in a rigid 3D tetrahedral network; extremely hard; does not conduct electricity (no delocalised electrons). Graphite: each C atom forms 3 covalent bonds in hexagonal layers with weak forces between layers (layers slide → soft/lubricant); 1 delocalised electron per carbon moves along layers to conduct electricity. | | | | 31 | Define oxidation and reduction both in terms of oxygen transfer and in terms of electron transfer (OIL RIG). | In terms of oxygen: Oxidation is gain of oxygen; Reduction is loss of oxygen. In terms of electrons (OIL RIG): Oxidation Is Loss of electrons (e.g., Mg → Mg²⁺ + 2e⁻); Reduction Is Gain of electrons (e.g., Cu²⁺ + 2e⁻ → Cu). | | | | 32 | What are the discharge rules at the cathode and anode during the electrolysis of an aqueous ionic solution (e.g., NaCl(aq) or CuSO4(aq))? | Cathode (-): Hydrogen gas (2H⁺ + 2e⁻ → H2) is produced UNLESS the metal ion is less reactive than hydrogen (such as Cu²⁺ or Ag⁺, where solid metal is plated). Anode (+): Oxygen gas (4OH⁻ → O2 + 2H2O + 4e⁻) is produced UNLESS the solution contains a halide ion (Cl⁻, Br⁻, I⁻), in which case the halogen gas (e.g., Cl2) is discharged. | | | --- Study this deck interactively with FSRS-6 spaced repetition, audio review, and multiple-choice mode at [Flashcards World](https://flashcards.world/flashcards/sets/42943c60-ddfc-4a15-a136-075f70e4584d/).