Chem paper1 atom group

• Electrons


  Exist in energy levels or shells
• Maximum electrons in energy levels

  • First energy level: 2
  • Second energy level: 8
  • Third energy level: 8
• Noble gases


  • Have a full outer energy level
  • Are unreactive
• Ionic bonding


  Occurs when a metal reacts with a non-metal
• Ionic bonding between lithium and fluorine

  1. Lithium atom loses outer electron

  2. Fluorine atom gains electron

  3. Both atoms achieve full outer energy level
• Lithium ion


  Atom with 3 protons and 2 electrons, overall +1 charge
• Fluoride ion


  Atom with 9 protons and 10 electrons, overall -1 charge
• During ionic bonding, group 1 metals lose 1 electron forming a +1 ion, and group 7 non-metals gain 1 electron forming a -1 ion
• Ionic bonding example


  • Sodium and chlorine
• Ionic bonding between sodium and chlorine


  1. 1 electron passes from sodium atom to chlorine atom

  2. Both atoms achieve full outer energy level