d-block elements

• d-block elements are located between group 2 and group 13 of the periodic table
• from scandium and zinc 3d sub-shells have the highest energy and electrons are added to the 3d orbitals
• d-block elements are metallic, displaying typical physical properties of metals
• d-block elements have high melting and boiling points, shiny appearance, conduct electricity and heat.
• the reactivity of d-block elements increases down the group due to an increase in atomic radius
• transition metals form coloured compounds with oxygen or chlorine
• scandium - 1s2, 2s2, 2p6, 3s2, 3p6, 3d1, 4s2
• chromium and copper Do NOT follow expected principle for placing electrons singly in orbitals before pairing.
• half- filled d5 sub-shell and fully filled d10 sub-shell give additional stability to atoms of chromium and copper
• electron configuration for iron, and its common ions Fe2+ and Fe3+:

  • Fe atom - 1s2, 2s2, 2p6, 3s2, 3p6, 3d6, 4s2.
  • Fe2+ ion - 1s2, 2s2, 2p6, 3s2, 3p6, 3d6.
  • fe3+ ion - 1s2, 2s2, 2p6, 3s2, 3p6, 3d5.
• what are the common ions in Fe?

  Fe2+ and Fe3+
• zinc only forms Zn2+ ion by the loss of two of it 4s electrons

  • electron configuration of zinc - 1s2, 2s2, 2p6, 3s2, 3p6, 3d10, 4s2.
  • Zn2+ electron configuration - 1s2, 2s2, 2p6, 3s2, 3p6, 3d10.