C4

• Group 1 - Alkali metals


  • They have characteristic properties due to the single electron in their outer shell
  • Metals in group one react vigorously with water to create an alkaline solution and hydrogen
  • They all react with oxygen to create an oxide
  • They all react with chlorine to form a white precipitate
  • The reactivity of the elements increases going down the group
• Identifying the products of chemical reactions

  1. Describe tests to identify selected gases

  2. Describe tests to identify aqueous cations and aqueous anions

  3. Describe how to perform a flame test

  4. Identify species from test results

  5. Interpret flame tests to identify metal ions

  6. Describe the advantages of instrumental methods of analysis

  7. Interpret an instrumental result given appropriate data in chart or tabular form, when accompanied by a reference set of data in the same form
• Carbon dioxide test


  Bubble the gas through limewater (carbon hydroxide) and it will turn milky (cloudy)
• Chlorine test


  When damp litmus paper is put into chlorine gas the litmus paper is bleached and turns white
• Hydrogen test


  Use a burning splint held at the open end of a test tube of the gas, creates a 'squeaky pop' sound
• Oxygen test


  Uses a glowing splint inserted into a test tube of the gas, splint relights in oxygen
• Aqueous cation tests


  • Few drops NaOH
  • Excess NaOH
• Aqueous cation test results

  • Calcium: White precipitate forms
  • Copper(II): Blue precipitate forms
  • Iron(II): Green precipitate forms
  • Iron(III): Orange-brown precipitate forms
  • Zinc: White precipitate forms, Precipitate re-dissolves
• Carbonate test


  Carbonates react with dilute acids to create carbon dioxide, this gas can be bubbled through limewater, if the limewater goes cloudy, the gas is CO2
• Halide test


  First add dilute nitric acid, followed by silver nitrate solution. Chloride gives a white precipitate, bromide gives a cream precipitate, iodide gives a yellow precipitate.
• Sulfate test


  First add dilute hydrochloric acid, followed by barium chloride solution. A white precipitate will form when sulfate ions are in this solution.
• Flame test


  Take a sample of the metal and hold on a spatula in a flame from a Bunsen burner and witness the colour that the flame turns dependent on the metal being tested
• Group 0 - Noble gases

  • They have 8 electrons in their outer shell (except helium, which has 2)
  • They are unreactive and do not easily form molecules, because they have a stable arrangement of electrons
  • The boiling points of the noble gases increase with increasing relative atomic mass (going down the group)
• Flame test results


  • Lithium: Crimson
  • Sodium: Yellow
  • Potassium: Lilac
  • Copper(II): Green
  • Calcium: Orange-red
• Instrumental methods of analysis

  • Elements and compounds can be detected and identified using instrumental methods of analysis, these are accurate, sensitive and rapid
• Group 7 - The halogens


  • Similar reactions due to their seven electrons in their outer shell
  • Non-metals and consist of molecules made of pairs of atoms
  • They react with metals to form ionic compounds in which the halide ion carries a -1 charge
  • A more reactive halogen can displace a less reactive in an aqueous solution of its salt
  • The element is less reactive because the higher the energy level of the outer electrons, the less easily electrons are gained (attracted to the positive nucleus)
  • The higher its relative molecular mass, melting and boiling points
• Observed simple properties of Groups 1, 7 and 0 depend on the outer shell of electrons of the atoms
• Properties of groups can be predicted from given trends down the groups
• Transition metals


  • Are harder and stronger
  • Have higher melting points (except for mercury) and higher densities
  • Much less reactive and don't react as vigorously with oxygen or water
  • They have ions with many different charges
  • Form coloured compounds
  • Are useful as catalysts
• Transition metals referred to as examples: Cr, Mn, Fe, Co, Ni, Cu
• Reactivity of metals


  • Left hand side of periodic table forms positive ions, right hand side forms negative ions (to gain stable electron arrangement like noble gases)
  • The group an element is in indicates how many electrons are in its outer shell
• Reactivity of metals with water or dilute acids

  1. Metals react by forming positive ions

  2. A metal that tends to form a positive ion more than another is more reactive

  3. Only the most reactive metals will react with dilute acids: Metal + dilute acid → salt + hydrogen

  4. Most metals will react with water, but some very unreactive ones won't: Metal + water → metal hydroxide + hydrogen
• Order of reactivity of metals can be deduced from experimental results