C1-Atomic structure

• What does the reaction between iron(II) sulphate and sodium hydroxide produce?

  Iron(II) hydroxide and sodium sulphate
• What are the state symbols used in chemical equations?

  • (s) — solid
  • (l) — liquid
  • (g) — gas
  • (aq) — aqueous solution (dissolved in water)
• Why must a chemical equation obey the law of conservation of mass?

  Because the number of atoms of each element must be the same on both sides of the equation
• What is the balanced equation for the reaction of hydrogen gas with oxygen gas to form water?

  2H₂(g) + O₂(g) → 2H₂O(l)
• What are the key points regarding balanced equations?

  • Balanced equation reaction
  • Total mass of reactants = total mass of products
  • Relative numbers of reactants and products can be calculated
  • State symbols provide additional information
  • Understanding balanced equations gives important quantitative information
• What is the definition of a mixture?

  A mixture is a combination of two or more substances that can be separated by physical methods
• How do mixtures differ from compounds?

  Mixtures are physically mixed, while compounds are chemically combined
• What are the methods of separating mixtures?

  • Simple distillation
  • Fractional distillation
  • Filtration
  • Crystallisation
• What is the purpose of filtration in separating mixtures?

  To separate a insoluble solute from a solvent
• What is the filtrate in filtration?

  The liquid that passes through the filter paper
• How does crystallisation separate a solid from a solution?

  By evaporating some of the water and allowing crystals to form as the solution cools
• What are the key points about separating mixtures?

  • Mixtures can be separated using physical methods
  • Different properties: boiling point, solubility, and particle size
  • Simple distillation, fractional distillation, filtration, and crystallisation are techniques
• What is the main purpose of fractional distillation?

  To separate liquids based on their boiling points
• Why is fractional distillation more effective than simple distillation?

  Because it allows for many condensation and evaporation cycles
• What happens to the vapour in fractional distillation as it rises up the fractionating column?

  It cools and condenses on the glass beads, then re-evaporates
• What is the role of the condenser in fractional distillation?

  To collect the substance with the lowest boiling point
• What is paper chromatography used for?

  To separate substances from a mixture
• How does the solvent affect the results of paper chromatography?

  The type of solvent influences the separation of substances on the paper
• What are the key points about paper chromatography?

  • Effective for separating mixtures of liquids
  • Rate of movement depends on solubility
  • Separation occurs due to different attractions between molecules and paper
• What did John Dalton describe atoms as?


  Solid spheres that are different for different elements
• What did Thomson's experiments reveal about atoms?


  That atoms contain negatively charged particles called electrons
• What is the plum pudding model?


  A model suggesting that atoms are spheres of positive charge with negative charge embedded throughout
• What did Rutherford's gold foil experiment demonstrate?

  That most of the atom is empty space with a small, dense nucleus
• What is the significance of energy levels in atomic structure?

  Electrons exist in specific energy levels or shells, not randomly
• What are isotopes?

  Atoms of the same element with different numbers of neutrons
• How do isotopes differ from each other?

  They have the same number of protons but different mass numbers
• What are the key points about the history of the atom?

  • Democritus- indivisible atoms
  • Dalton's solid sphere model
  • Thomson's discovery of electrons and plum pudding model
  • Rutherford's gold foil experiment revealing the nucleus
  • Neil's Bohr-Electrons in specific energy levels
  • Existence of isotopes
• What did the results of the atom experiments suggest about the structure of the atom?

  Most of the atom is empty space with a small, dense, positively charged nucleus.
• How do electrons exist in an atom according to the discovery of energy levels?

  Electrons exist in specific energy levels or shells, not in random orbits.
• What does the spectrum of light emitted by excited atoms indicate about electron energy levels?

  The spectrum consists of discrete lines, indicating specific changes in energy are possible.
• What are isotopes?

  Isotopes are atoms of the same element with different numbers of neutrons.
• How do isotopes differ in terms of atomic number and mass number?

  Isotopes have the same atomic number but different mass numbers due to varying neutrons.
• What is the atomic number of an element?

  The atomic number is the number of protons in the nucleus of each atom of that element.
• How does the atomic number determine the position of an element in the periodic table?

  The atomic number dictates the position of the element in the periodic table.
• What is the mass number of an atom?

  The mass number is the total number of protons and neutrons in the nucleus.
• How do you calculate the number of neutrons in an atom?

  Number of neutrons = mass number – atomic number.
• How many protons, neutrons, and electrons are in an atom of $^{24}Mg$?


  12 protons, 12 neutrons, and 12 electrons.
• What are the relative charges and masses of protons, neutrons, and electrons?

  Protons: +1 charge, mass 1; Neutrons: 0 charge, mass 1; Electrons: -1 charge, negligible mass.
• What is the relationship between protons and electrons in a neutral atom?

  The number of protons equals the number of electrons in a neutral atom.
• What is an ion?

  An ion is an atom that has lost or gained one or more electrons.