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4th period d-block elements 4th Period. d-block elements  center block of periodic table transition elements d-sub level partially filled in one or more.

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Presentation on theme: "4th period d-block elements 4th Period. d-block elements  center block of periodic table transition elements d-sub level partially filled in one or more."— Presentation transcript:

1 4th period d-block elements 4th Period

2 d-block elements  center block of periodic table transition elements d-sub level partially filled in one or more oxidation state (ion charge) Except: Zn (full d-sublevel in all oxidation states), Sc (common ion Sc 3+ has no d electrons)

3  transition elements dense hard metallic relatively constant ionization energy similar chemical and physical properties 2 + oxidation state most stable (ex: Cu 2+ )

4  transition elements … 1.have a variety of stable oxidation states. 2.form complex ions. 3.form colored ions. 4.engage (take part in) in catalytic activity.

5 1. Variation in oxidation states (ions)  3d and 4s sublevels are similar in energy  4s e- most often lost = 2 + oxidation state (very stable!)  d-block has higher ENC than s- block, but ionization energy does not increase very much going across the period because 3d and 4s have similar energy

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7 Oxidation State  Vanadium (V) reacts with zinc amalgam (combination of two metals). Zinc is a reducing agent (donates electrons) to change the oxidation state of the vanadium

8  Play the movie!

9  higher oxidation states are to the left of the d-block energy required to produce ions increases going to the right a half-filled shell is more stable than 3 or 5 valence electrons

10 ScTiVCrMnFeCoNiCuZn 4s 2 3d 1 4s 2 3d 2 4s 2 3d 3 4s 1 3d 5 4s 2 3d 5 4s 2 3d 6 4s 2 3d 7 4s 2 3d 8 4s 1 3d 10 4s 2 3d 10 +2, +3, +4 +2, +3, +4, +5 +2, +3, +6 +2, +3, +4, +7 +2, , +2 ionization energy increases higher oxidation states to left

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12 2. Complex ions  d-block ions have low-energy unfilled d and p orbitals can accept a pair of non-bonding electrons (ligand) form a bond between ligand and metal ion ligand + metal ion = complex ion ex: water, ammonia (NH 3 ), Cl -  all donate electron pair

13 M Cl Complex ions tetrahedral= 4 octahedral = 6 ligands ligands 4 sides8 sides

14 tetrahedron (tetrahedral)

15 Octahedron (octahedral)

16  number of ligands = coordination number  can bond once (monodentate)  or twice (bidentate)  complex ions: stabilize transition metal affect solubility affect color bite

17  Isomerism – compounds with the same formula, but different structures and bonding found in complex ions

18  stereoisomerism: isomers with different arrangements of atoms (bonding is the same) cis (next to each other) trans (opposite)

19 3. Colored Ions  In most atoms, all d orbitals have the same energy.  In complex ions, d orbitals are on TWO different energy levels.  If surrounded by ions or some kinds of molecules, an electric field effects the different orbitals differently.

20  White light passes through a transition metal and some frequencies are absorbed, some reflected  Some d electrons are moved to the higher energy d orbital.

21  Cu 2+ : red and yellow absorbed blue and green reflected  Color depends on ions surrounding transition element.  If no d electrons (Sc 3+, Ti 4+ ) colorless (no color)

22 white light lower d orbital higher d orbital

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24 4. Catalytic Activity  catalyst: speeds up or begins a reaction by using a different reaction “ pathway ”  because: complex ions can donate an e- pair they have many stable oxidation states so they can easily gain and lose electrons in reactions Fe 2+ can easily become Fe 3+ and still be stable!

25 d-Block Catalysts  heterogeneous (common): the surface of the transition metal or compound is an “ active ” surface for the reaction to occur on requires less activation energy activation energy: the level of energy needed for a reaction to happen.

26 Heterogeneous Catalyst  2H 2 O 2 (aq)  2H 2 O(l) + O 2 (g) reactants bond to the solid metal (Mn) surface which brings the molecules together.  N 2 (g) + 3H 2 (g)  2NH 3 (g) Haber Process Catalyst not used up in reaction MnO 2 Fe

27  homogeneous: the catalyst is in the same phase (state) as the reactants metal ion oxidized (e - lost) in one stage, then reduced (e - gained) in the second

28 Homogeneous H 2 O 2 (aq) + I - (aq)  I 2 (s) + H 2 O(l) veeeeery slooooow reaction, very high activation energy H 2 O 2 (aq) + 2H + (aq) + 2Fe 2+ (aq)  2H 2 O(l) + 2Fe 3+ 2I - (aq) + 2Fe 3+ (aq)  I 2 (s) + 2Fe 2+ (aq) two reactions are much faster, have lower activation energy oxidized reduced


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