15.1 - Atoms and Ions of Transition Metals

• what's a transition metal?

  a d-block element that forms one or more stable ions with an incompletely filled d orbital
• why are zinc and scandium not transition metals?

  they only for Zn2+ and Sc3+ ions which have empty and full d subshells
• electronic configurations for transition metals

  4s and 3d orbitals overlap but because 4s is on a lower energy level it fills up first (Aufbau principle) despite 3d being nearer to the nucleus
• exceptions for electronic configuration of transition metals

  chromium and copper
• reason for chromium and copper having different electronic configurations

  half filled and fully filled d orbitals are more stable because it's more symmetrical so there's an equal distribution of charges around the nucleus

  also filling the 4s first would create additional repulsion
• which electrons are removed first when transition metals form ions

  4s electrons because electrons in 3d subshell repel 4s electrons to a higher energy level
• types of ions transition metals form

  simple ions and complex ions with varying oxidation states as they can lose different numbers of electrons
• most common reaction of transition metals

  redox reactions
• why is Fe3+ more stable than Fe2+?

  it's only got unpaired electrons in 3d subshell so less repulsion

  fe2+ has one paired electron in 3d subshell