15.2/3 - Defining Transition Metals

• characteristics of transition metals

  hard metals with useful mechanical properties, high melting and boiling points

  compounds have variable oxidation numbers

  form coloured ions in solution

  elements and compounds acts as catalysts

  form complex ions involving monodentate, bidentate and polydentate ligands
• structure of transition metals

  close packed structure where each atom is in contact with 12 other atoms - 6 in the same layer, 3 above and 3 below
• ionic radii

  small due to large nuclear charge which pulls electrons closer
• bonding

  strong metallic
• comparison to s-block metals

  higher melting and boiling points, higher densities and tensile strength due to stronger metallic bonding due to close packing and ionic radii
• reactivity

  less reactive than s-block metals

  react very slowly with dilute acids because it is protected by a thin, unreactive layer of oxide
• least reactive d-block element

  copper