Metals Form Alloys Metals do not combine with metals. They form Alloys which is a solution of a metal in a metal. Examples are steel, brass, bronze and pewter.
C. Johannesson NH 4 + 1 N × 5e - = 5e - 4 H × 1e - = 4e - 9e - H H N H H - 1e - 8e - - 8e - 0e - C. Polyatomic Ions
C. Johannesson D. Resonance Structures Molecules that can’t be correctly represented by a single Lewis diagram. Actual structure is an average of all the possibilities. Show possible structures separated by a double-headed arrow.
C. Johannesson D. Resonance Structures O O S O O O S O O O S O n SO 3
Exceptions to the Octet Rule Molecules containing atoms of Group 3A elements, particularly boron and aluminum Aluminum chloride : : : FB F F ClAl Cl Cl 6 electrons in the valence shells of boron and aluminum Boron trifluoride :: :: :: : : : : : : : : :
Exceptions to the Octet Rule Atoms of third-period elements have 3d orbitals and may expand their valence shells to contain more than 8 electrons – phosphorus may have up to 10
Exceptions to the Octet Rule – sulfur, another third-period element, forms compounds in which its valence shell contains 8, 10, or 12 electrons
C. Johannesson A. VSEPR Theory Valence Shell Electron Pair Repulsion Theory Electron pairs orient themselves in order to minimize repulsive forces.
C. Johannesson A. VSEPR Theory Types of e - Pairs – Bonding pairs - form bonds – Lone pairs - nonbonding e - Lone pairs repel more strongly than bonding pairs!!!
C. Johannesson A. VSEPR Theory Lone pairs reduce the bond angle between atoms. Bond Angle
C. Johannesson Draw the Lewis Diagram. Tally up e - pairs on central atom. – double/triple bonds = ONE pair Shape is determined by the # of bonding pairs and lone pairs. Know the 8 common shapes & their bond angles! B. Determining Molecular Shape
C. Johannesson C. Common Molecular Shapes 2 total 2 bond 0 lone LINEAR 180° BeH 2
C. Johannesson 3 total 3 bond 0 lone TRIGONAL PLANAR 120° BF 3 C. Common Molecular Shapes
C. Johannesson C. Common Molecular Shapes 3 total 2 bond 1 lone BENT <120° SO 2
C. Johannesson 4 total 4 bond 0 lone TETRAHEDRAL 109.5° CH 4 C. Common Molecular Shapes
C. Johannesson 4 total 3 bond 1 lone TRIGONAL PYRAMIDAL 107° NH 3 C. Common Molecular Shapes
C. Johannesson 4 total 2 bond 2 lone BENT 104.5° H2OH2O C. Common Molecular Shapes
C. Johannesson 5 total 5 bond 0 lone TRIGONAL BIPYRAMIDAL 120°/90° PCl 5 C. Common Molecular Shapes
C. Johannesson 6 total 6 bond 0 lone OCTAHEDRAL 90° SF 6 C. Common Molecular Shapes
C. Johannesson PF 3 4 total 3 bond 1 lone TRIGONAL PYRAMIDAL 107° D. Examples
C. Johannesson CO 2 2 total 2 bond 0 lone LINEAR 180° D. Examples