Topic 13 - Periodicity

Ionic properties High melting and boiling point Conduct electricity in molten and aqueous states Crystalline solids Soluble

Giant covalent properties High melting and boiling point Non conductor Giant covalent structure Insoluble in water

Covalent properties – Low melting and boiling points – Non conductors in molten state – Covalent molecular structure

Intermediate properties Al 2 Cl 6 is covalent – Although Al is metal, in many of its compounds it is more typical of nonmetal; small size/high charge – AlCl 3 sublimes at low temp to Al 2 Cl 6 molecules Al 2 O 3 is ionic but can be macromolecular

Explanation of physical states of oxides of period 3 [86] Formulas and bonding of oxides Na 2 O - ionic MgO - ionic Al 2 O 3 – ionic SiO 2 – giant covalent P 4 O 6 and P 4 O 10 – molecular covalent SO 2 and SO 3 – molecular covalent Cl 2 O and Cl 2 O 7 – molecular covalent

Acid-base character of oxides of period 3 [87-88] Formulas and bonding of oxides Na 2 O - basic MgO - basic Al 2 O 3 and Al 4 O 6 - amphoteric SiO 2 – amphoteric P 4 O 6 and P 4 O 10 – acidic SO 2 and SO 3 – acidic Cl 2 O and Cl 2 O 7 – acidic

Exercises page 88

Explanation of physical states of chlorides of period 3 [89-92] Formulas and bonding of chlorides NaCl – ionic MgCl 2 - ionic AlCl 3, Al 2 Cl 6 – covalent, but dissociates into ions in water SiCl 4 – molecular covalent PCl 3 and PCl 5 – molecular covalent Cl 2 – molecular covalent

Period 3 chlorides + water NaCl produce neutral solution MgCl 2 produce a weakly acidic solution Al 2 Cl 6, SiCl 4, PCl 3, PCl 5, Cl 2 produce acidic solutions Exercise 17 page 92

The d-block elements [94-95] Discussion limited to first row The transition metals are a subset of the d- block elements that have partially filled d- sublevels in their ionic states Sc and Zn are not typical transition metals – Do not have partially filled d-block as ions

Transition metals [94-95] Common chemical properties of transition metals – Variable oxidation states (ionic charge) – Complex ion formation – Colored ions – Catalytic activity – Remember, Sc and Zn are not transition metals, do not share these common properties

The d-block elements – variable oxidation states [95-96] e configurations and common charges ScTiVCrMnFeCoNiCuZn 32, 3,4 2 3,4,5 2,3,6 4,5 2,4 3,5,6,7 2,3 4,5,6 2 3,4,5 2 3,4 1,2 3 2

The d-block elements – variable oxidation states [95-96] Exercises page 97

The d-block elements – colored ions [97-101] Sc – no color Ti – violet V – white, green, brown, purple Cr – green or orange Mn – purple Fe – green or red brown Co – blue or pink Ni – green Cu – blue green Zn – no color

The d-block elements – colored ions [97-101]

The d-block elements – complex ion formation [ ] Definitions – Ligand – an ion or molecule that coordinates to a metal atom or ion to form a complex – Coordinates – the ligand donates an non bonding electron pair to the metal atom or ion – Dative bond – one where both electrons in a bond are donated by one species – Metal complexes – ligands bonded to a central metal atom or ion – Coordination number – number of particles around the central metal atom or ion

The d-block elements – complex ion formation [ ] Common ligands – OH -,H 2 O, NH 3, Cl -, CN Examples – [Cu(NH 3 ) 4 ]Cl 2, Cu(H 2 O) 6 +2, [CuCl 4 ] -2 – Charge on copper is +2 – What would the shapes be

The d-block elements – complex ion formation [ ] Most transition metals exist as a hexahydrated complex ion in aqueous solution – Coordination number of 6 Coordination numbershape 6octahedral 4tetrahedral or square planar 2linear

The d-block elements – catalytic activity [ ] Catalytic behavior due to ability form complex ions – Close contact between ligands and also between ligand and metal Variety of stable oxidation states, readily gain and lose electrons Heterogeneous or homogeneous catalyst

The d-block elements – catalytic activity examples The Haber Process During the Contact Process for manufacturing sulphuric acid, sulphur dioxide has to be converted into sulphur trioxide.

The d-block elements – catalytic activity examples Nickel in hydrogenation reactions C 2 H 4 (g) + H 2 (g) → C 2 H 6 (g) Manganese (IV) oxide in the decomposition of hydrogen peroxide 2H 2 O 2 (aq) → 2H 2 O (l) + O 2 (g) Ni (s) MnO 2

Topic 13 questions 1. What is the most common charge in the first row of transition metals? 2. Explain why the transition metals are frequently colored. 3. Name the two first row d-block elements that are not transition metals. 4. Why does ammonia form complex ions with Co +2, but methane does not? 5. Explain one industrial application of a transition metal catalyst.