Atomic structure

• Group one metals


  Also called the alkali metals
• Group one metals have one electron in their outer energy level
• Reaction of group one metals with oxygen

  1. Lithium reacts with oxygen to form lithium oxide

  2. Sodium reacts with oxygen to form sodium oxide

  3. Potassium reacts with oxygen to form potassium oxide
• As we move down group one

  The metals react more rapidly with oxygen
• Lithium atom


  • Has one outer electron
  • Transfers outer electron to oxygen atom
• Oxygen atom


  • Has six outer electrons
  • Requires one more electron to have a full outer energy level
• Reaction of lithium and oxygen

  1. Lithium atom transfers outer electron to oxygen atom

  2. Lithium atom becomes a positive lithium ion

  3. Oxygen atom becomes a negative oxide ion
• Oxygen molecules contain two oxygen atoms
• Equations can be written for the reactions of sodium and potassium with oxygen by changing the metal symbol
• Group one metals react very rapidly with oxygen
• Reaction of lithium and chlorine

  1. Lithium atom transfers outer electron to chlorine atom

  2. Lithium atom becomes a positive lithium ion

  3. Chlorine atom becomes a negative chloride ion
• Equations can be written for the reactions of sodium and potassium with chlorine by changing the metal symbol
• Group one metals also react very rapidly with chlorine
• Group one metals


  The alkaline metals
• Group one metals

  • All have one electron in their energy level
• Group one metals reacting with water

  1. Lithium reacts with water

  2. Sodium reacts with water

  3. Potassium reacts with water
• Effervescence


  Fizzing, indicating a gas is being produced
• Alkaline solution


  Indicated by universal indicator turning purple
• Lithium reacting with water

  Produces lithium hydroxide and hydrogen
• As we move down group one


  The group one metals get more reactive
• Reason for increased reactivity down group one

  • Increasing atomic radius decreases attraction between nucleus and outer electron
  • Increasing shielding from inner electrons decreases attraction between nucleus and outer electron
• The outer electron is less attracted to the nucleus as we move down group one, making it easier to lose