Paper 1

• What are all substances made of?

  Atoms
• What is an atom?

  The smallest part of an element that can exist
• How many elements are there approximately?

  About a hundred
• What are compounds formed by?

  Chemical reactions where different elements join together
• How can a compound be represented?

  Using a chemical symbol formula
• What does a compound contain?

  Two or more different elements that have been chemically combined
• What is the naming rule for ionic compounds with one metallic and one non-metallic element?

  The name of the metal is used as is, and the first syllable of the non-metal is combined with "ide"
• Give an example of an ionic compound.

  Iron oxide
• What is the naming rule for compounds containing three elements with oxygen?

  Use the metal name, the first syllable of the non-metal, and add "ate"
• What is a mixture?

  Two or more elements or compounds that are not chemically combined
• How can mixtures be separated?

  By physical processes rather than chemical reactions
• What are the five physical processes used to separate mixtures?

  • Filtration
  • Crystallization
  • Distillation
  • Fractional distillation
  • Chromatography
• What is filtration used for?

  To separate an insoluble solid from a liquid
• What is the residue in filtration?

  The insoluble solid left on the filter paper
• What is crystallization used for?

  To separate a soluble substance from a liquid
• How does distillation separate mixtures?

  By using the boiling points of the liquids
• What is the difference between simple distillation and fractional distillation?

  Simple distillation separates two liquids, while fractional distillation separates multiple liquids
• What is chromatography used for?

  To analyze mixtures of liquids
• What is the stationary phase in paper chromatography?

  The chromatography paper
• What is the mobile phase in paper chromatography?

  The solvent that passes through the stationary phase
• Why is it important to draw the start line in pencil in chromatography?

  To prevent the start line from running and obscuring results
• Where are protons and neutrons found in the atom?

  In the nucleus at the center
• How many electrons can fit in the first shell of an atom?

  Two electrons
• How many electrons can fit in the second shell of an atom?

  Eight electrons
• What is the atomic number of an element?

  The number of protons in an atom
• What does the mass number indicate?

  The total number of particles in the nucleus
• How do you calculate the number of neutrons in an atom?

  By subtracting the number of protons from the mass number
• What are the relative masses of protons and neutrons?

  Both are one
• What is the relative charge of a proton?

  Plus one
• What is the relative charge of an electron?

  Minus one
• What is the relative charge of a neutron?

  Zero
• How small are atoms?

  0.1 nanometers across
• What are isotopes?

  Atoms of the same element with the same number of protons but different numbers of neutrons
• How do you calculate the relative atomic mass of a sample containing isotopes?

  By calculating the weighted average of the isotopes' masses
• If a sample contains 90% lithium-7 and 10% lithium-9, what is the relative atomic mass?

  1. 2
• What did John Dalton's model of the atom propose?

  Atoms are solid spheres that cannot be broken down further
• What was J.J. Thompson's contribution to atomic theory?

  He discovered electrons and proposed the plum pudding model
• What did Ernest Rutherford's alpha scattering experiment demonstrate?

  Most of the atom is empty space with a concentrated nucleus
• What did Niels Bohr propose about electron movement?

  Electrons orbit the nucleus at fixed distances
• What did James Chadwick discover?

  The neutron