Definitions

• What is an atom?

  The smallest part of an element
• What is the atomic nucleus?

  Positively charged center of an atom
• What is a proton?

  Positively charged particle in the nucleus
• What is a neutron?

  Neutral particle in the nucleus of an atom
• What is an electron?

  Negatively charged particle orbiting the nucleus
• What is an electron shell?

  Energy levels occupied by electrons
• What is atomic number?

  The number of protons in the nucleus
• What is mass number?

  Total number of protons and neutrons
• What is an ion?

  An atom or molecule with an electric charge
• What is an isotope?

  Atoms with the same protons but different neutrons
• What are the key points of Dalton's Atomic Theory?

  • Atoms are tiny, solid, indivisible spheres
  • Different elements consist of different types of atoms
• Describe the Plum Pudding Model.

  • Atom is a ball of positive charge
  • Negative electrons are scattered throughout
• What does the Nuclear Model propose?

  • Most mass and positive charge in nucleus
  • Electrons orbit around the nucleus
• What is the Bohr Model of the atom?

  • Electrons orbit the nucleus in fixed energy levels
  • Explains light emission at specific wavelengths
• What does the Quantum Mechanical Model describe?

  • Electrons in probability clouds called orbitals
  • Not in fixed paths around the nucleus
• What is the periodic table?

  Table of elements arranged by atomic number
• What is a group in the periodic table?

  Columns of elements with similar properties
• What is an element?

  A substance made of one type of atom
• What is a compound?

  A substance made of chemically combined atoms
• What is a mixture?

  A combination of elements or compounds not combined
• What are alkali metals?

  Elements in Group 1 of the periodic table
• What are halogens?

  Elements in Group 7 of the periodic table
• What are noble gases?

  Elements in Group 0 of the periodic table
• What are metals?

  Elements that form positive ions
• What are non-metals?

  Elements that form negative ions
• What are transition metals?

  Metallic elements in the middle of the periodic table
• What are the main separation techniques in chemistry?

  • Chromatography: separates mixtures by distribution
  • Filtration: separates solids from liquids
  • Crystallisation: produces solid crystals from solutions
  • Simple distillation: separates liquids by boiling points
  • Fractional distillation: separates mixtures by boiling points
• What is chromatography?

  A technique to separate mixtures of chemicals
• What is filtration?

  A technique to separate solids from liquids
• What is crystallisation?

  A technique to produce solid crystals from solutions
• What is simple distillation?

  A procedure to separate liquids with different boiling points
• What is fractional distillation?

  A method to separate substances by boiling points
• What is displacement in chemistry?

  A reaction where a more reactive element displaces another
• What is relative atomic mass?

  An average value considering isotope abundance