Chemistry actual ps

• Atom


  The smallest part of an element that can exist
• Compound


  A substance formed by chemical reactions where different elements join together
• Compound


  Contains two or more different elements which have been chemically combined in fixed proportions
• Naming ionic compounds


  1. Name of metal

  2. First syllable of non-metal

  3. Add 'ide'
• Naming compounds with oxygen


  1. Name of metal

  2. First syllable of non-metal

  3. Add 'ate'
• Mixture


  Two or more elements or compounds that are not chemically combined together
• Physical processes to separate mixtures

  • Filtration
  • Crystallization
  • Distillation
  • Simple distillation
  • Fractional distillation
  • Chromatography
• Filtration


  • Separates insoluble solids from liquids
• Crystallization


  • Evaporates liquid to leave behind soluble salt crystals
• Distillation


  • Separates liquids based on their different boiling points
• Simple distillation


  • Separates two different liquids
• Fractional distillation


  • Separates multiple different liquids
• Chromatography


  • Separates substances based on how well they are retained by a stationary phase while a mobile phase passes through
• In paper chromatography, the start line must be drawn in pencil and the solvent shouldn't come above that line
• Nuclear model of the atom


  Protons and neutrons in the nucleus, electrons orbiting the outside
• Atom


  • Electrons fill shells, maximum 2 in first shell, 8 in second and third shells
• Atomic number


  Number of protons in the nucleus
• Mass number


  Total number of protons and neutrons in the nucleus
• Relative mass


  Protons and neutrons have a mass of 1, electrons have a very small mass
• Relative charge


  Protons +1, electrons -1, neutrons 0
• Atoms are 0.1 nanometers across, with the nucleus being 1/10,000 of the atom's radius
• Isotopes


  Atoms of the same element with the same number of protons but different numbers of neutrons
• Calculating relative atomic mass of a sample with two isotopes


  Calculate 90% of the mass of one isotope and 10% of the mass of the other isotope, then add them together
• John Dalton's atomic model


  Atoms as solid spheres that can't be broken down further
• J.J. Thomson's atomic model


  Electrons embedded in a large ball of positive charge, like a plum pudding
• Ernest Rutherford's atomic model


  Positive nucleus at the centre, with electrons orbiting it
• Niels Bohr's atomic model


  Electrons orbiting the nucleus at fixed distances, in shells
• The periodic table key shows the atomic number at the bottom and the relative atomic mass at the top
• Groups


  Columns in the periodic table, elements have the same number of electrons in their outer shell
• Periods


  Rows in the periodic table, elements have the same number of electron shells
• Metals and non-metals


  Metals on the left and bottom, non-metals on the right and top
• Metallic elements


  • Form positive ions, are malleable, conductive, and have high melting points
• The periodic table is called 'periodic' because the same properties occur at regular intervals
• Early periodic tables


  Grouped elements by chemical properties and atomic weight, not atomic number
• Dmitri Mendeleev


  Left gaps in the periodic table for undiscovered elements, and accurately predicted their properties
• Groups in the periodic table


  • Group 1 (alkali metals)
  • Group 2
  • Group 6
  • Group 7
  • Transition metals
• Group 1 (alkali metals)


  • Soft, highly reactive metals with 1 electron in their outer shell
• Alkali metals react with oxygen to form metal oxides
• Three specific groups in the periodic table

  • Group 1 (Alkali metals)
  • Group 7 (Halogens)
  • Group 0 (Noble gases)
• Alkali metals


  Soft, highly reactive metals with one electron in their outer shell