Topic 2: Bonding, Structure and the Properties of Matter

• States of matter

  • Solids
  • Liquids
  • Gases
• Solids

  Particles are packed together in a regular pattern with almost no spaces between them
• Liquids

  Particles are close together with not many spaces between them and can flow from place to place
• Gases

  Particles are widely spaced and move quickly and randomly
• Changing state of a substance

  1. Heating solid to liquid (melting)

  2. Cooling liquid to solid (freezing)

  3. Heating liquid to gas (boiling)

  4. Cooling gas to liquid (condensing)
• Melting point


  The temperature at which a solid changes to a liquid
• Boiling point

  The temperature at which a liquid changes to a gas
• Solids are extremely hard to compress
• Liquids are extremely hard to compress
• Gases are extremely easy to compress
• Particles in a solid can vibrate but cannot move from place to place
• Particles in a liquid can move
• Particles in a gas move quickly and randomly
• Forces of attraction

  Stronger forces require more energy to break, resulting in higher melting and boiling points
• Candle wax has a relatively low melting point due to weak forces of attraction between particles
• Sodium chloride has a very high melting point due to strong forces of attraction between particles
• Freezing

  Converting a liquid back to a solid by cooling
• Condensing


  Converting a gas back to a liquid by cooling
• Limitations of the simple particle model

  Assumes all particles are solid spheresAssumes no forces between particles
• The forces of attraction between particles have a major impact on the melting and boiling points of a substance
• Electrons

  Transferred during ionic bonding
• Ionic bonding

  1. Metal loses electron

  2. Non-metal gains electron

  3. Both achieve full outer energy level
• Noble gases

  • Full outer energy level
  • Stable
  • Unreactive
• The first energy level can hold a maximum of two electrons
• The second energy level can hold a maximum of eight electrons
• The third energy level can also hold eight electrons before the fourth energy level starts filling
• Elements react in order to achieve a full outer energy level
• Metals are on the left-hand side of the periodic table
• Non-metals are found on the right-hand side of the periodic table
• When a metal and a non-metal react

  Ionic bonding takes place
• Ion


  An atom with an overall charge
• Lithium ion

  Formed when lithium loses one electron, resulting in a one positive charge
• Fluoride ion


  Formed when fluorine gains one electron, resulting in a one negative charge
• During ionic bonding, group one metals lose one electron forming a one positive ion
• During ionic bonding, group seven non-metals gain one electron forming a one negative ion
• In the reaction between sodium and chlorine, one electron passes from the sodium atom to the chlorine atom
• Both sodium and chlorine achieve a full outer energy level
• This video describes how electrons are transferred during ionic bonding between group two metals and group six non-metals
• Ionic bonding between magnesium and oxygen

  1. Magnesium loses two electrons

  2. Electrons transferred to oxygen

  3. Magnesium becomes a two positive ion

  4. Oxygen becomes a two negative ion
• Magnesium ion

  Magnesium atom with a two positive charge