topic c2- bonding, structure- properties of matter

• ionic bonding

  • transferring electrons between elements, forming ions
  • when a metal and non-metal react
• magnesium chloride- ionic bonding

  • Mg loses 2 electrons
  • becomes Mg2+
  • loses 2 negative charges
  • Cl gains 1 electron each
  • becomes Cl-
  • gains 1 negative charge
• covalent bonding

  • sharing electrons between elements, forming covalent bonds
  • when two non-metals react
• hydrogen and nitrogen- covalent bonding

  • nitrogen (N) has 5 electrons on its outer shell (group 5 on periodic table), needing 3 more
  • hydrogen (H) has 1 needing 1 more
  • by sharing, each atom completes their outer shell
  • covalent bonds have been formed
• metallic bonding

  • delocalised (free to move) electrons in the outer shell are attracted to the positive charge on metal ion
  • these attractions hold the atom in a strong, regular structure
• substances held together by metallic bonding include:

  • alloys
  • elements
• properties of ionic bonding

  • metal + non-metal
  • high melting and boiling points
  • electrical conductors when melted
  • electrons are transferred
• properties of covalent bonding

  • low melting and boiling points due to weak forces
  • don't conduct electricity
  • electrons are shared
• properties of metallic bonding

  • metal + metal
  • high melting and boiling points
  • good heat conductors
  • good electrical conductors due to delocalised electrons
• polymers

  • long chain of repeating units, called monomers
• solid to a liquid

  • melting
• liquid to a gas

  evaporation
• gas to a liquid

  condensation
• liquid to a solid

  freezing
• solid to a gas

  sublimation
• states of mass

  • melting
  • evaporation
  • condensation
  • freezing
  • sublimation
• properties of solids

  • fixed positions
  • vibrated to transfer energy
  • strong forces
• properties of liquids

  • fit base of container
  • constant movement, faster with heat
  • weaker forces
• properties of gases

  • fill container
  • random motion
  • very weak forces
• metals are good conductors of heat because

  their electrons are free to move