chem lab bonding 05

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By: paracleutus (20 month(s) ago)

very datailed and explainatory. thank you

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Chemistry Lab 2005: 

Chemistry Lab 2005 Coaches Clinic Hammond, IN October 2004 Patti Smith Ps7mucs@ucs.misd.net

Don’t Forget…..: 

Don’t Forget….. Safety Requirements! Description of the Competition! 2005 Topics Oxidation / Reduction (2nd year) Chemical Bonding (new)

Chemical Bonding: 

Chemical Bonding describe the formation of cations/anions discuss the characteristics of ionic bonds use electron dot formulas to predict formulas of ionic compounds use characteristics of ionic bonds to explain electrical conductivity of ionic solutions and when molten

Chemical Bonding cont:: 

Chemical Bonding cont: Given a set of unknown cations/anions, design and carry out a series of tests that will identify each one Use the theory of metallic bonds to explain the physical properties of metals Describe the arrangement of atoms in some common metallic crystal structures (face-centered, body-centered, simple cubic)

Chemical Bonding cont:: 

Chemical Bonding cont: Use electron dot structures to show the formation of single, double, and triple bonds Identify coordinate covalent bonding and resonance structures Use VSEPR theory to predict shapes of simple covalently bonded molecules (maximum of 6 electron pairs around central atom). Use electronegativity (and molecular shape when necessary) to classify a bond as covalent, polar covalent or ionic.

Chemical Bonding cont.:: 

Chemical Bonding cont.: Name and describe the weak attractive forces that hold groups of molecules together. Draw molecular, structural, electron dot formulas and orbital diagrams for molecules Identification of orbital hybridization may be included at the State and National level.

The Orbitron: a gallery of atomic orbitals and molecular orbitals on the WWW http://www.shef.ac.uk/chemistry/orbitron/ The Chemistry Coach: Bonding http://www.chemistrycoach.com/tutorials-1.htm#Bonding Excellent sites for shapes of molecules: http://www.chemmybear.com/shapes.html http://www.wpi.edu/Academics/Depts/Chemistry/Courses/CH1010/Stream1/concept3.html : 

The Orbitron: a gallery of atomic orbitals and molecular orbitals on the WWW http://www.shef.ac.uk/chemistry/orbitron/ The Chemistry Coach: Bonding http://www.chemistrycoach.com/tutorials-1.htm#Bonding Excellent sites for shapes of molecules: http://www.chemmybear.com/shapes.html http://www.wpi.edu/Academics/Depts/Chemistry/Courses/CH1010/Stream1/concept3.html Chemical Bonding sites

Electron Dot Structures: 

Electron Dot Structures All chemistry textbooks have a chart like this

Loss & Gain of electron(s): 

Loss & Gain of electron(s) Atoms are stable when they have an “octet” or Nobel gas configuration. Atoms form ions through the gain or loss of electrons Opposites attract and ionic compounds are formed

Formation of an Ionic Compound Using Electron Configurations : 

Formation of an Ionic Compound Using Electron Configurations Sodium looses 1 electron and chlorine gains one electron to form an “octet” or Nobel gas configuration.

Electron Dot Formula of an Ionic Compound: 

Electron Dot Formula of an Ionic Compound Magnesium atoms lose 2 electrons to become stable Nitrogen atoms gain 3 electrons to become stable 3 Mg ions (+6) and 2 nitrogen atoms (-6) = 0 net charge;)

Properties of Ionic Compounds: 

Properties of Ionic Compounds Usually solid crystals @ room temp (types of crystal structure & coordination number) Generally have high melting points Can conduct electricity when melted or dissolved in water Formula represents number of ions in a representative unit

Metallic Bonds: 

Metallic Bonds Metals are made up of closely packed cations rather than neutral atoms Valence electrons are mobile (sea of electrons) Metallic bonds consist of attractions of the free-floating valence electrons for the positively charged metal ions

Metallic Properties & Structures:: 

Metallic Properties & Structures: Good conductors of electricity Can be drawn into wires (ductile) Can be hammered or forced into shapes (malleable) Arranged in very compact & orderly patterns Alloys are a mixture of 2 or more elements, at least one of which is a metal

Single Covalent Bonds: 

Single Covalent Bonds Nitrogen needs 3 additional electrons to satisfy its octet but cannot remove them from hydrogen so they share electrons Carbon needs 4 additional electrons to satisfy its octet but cannot remove them from hydrogen so they share electrons

Double Bonds: 

Double Bonds Oxygen cannot remove 2 electrons from another oxygen so they share 2 pairs (double bond) Nitrogen cannot remove 3 electrons from another nitrogen so they share 3 pairs (double bond)

Coordinate Covalent Bonds: 

Coordinate Covalent Bonds Coordinate covalent bond is formed when one atom donates an unshared electron pair to the bond. In this case oxygen donates on of its unshared pairs. This is seen frequently in polyatomic ions!

Resonance : 

Resonance One or more of two equally valid electron dot structures of a molecule or polyatomic ion Actual bonding Is a hybrid , or mixture, of the resonance structures

VSEPR (valence shell electron pair repulsion theory): 

VSEPR (valence shell electron pair repulsion theory) electron pairs repel and molecules adjust their shapes so that their valence shell electrons are as far apart as possible

VSEPR continued: 

VSEPR continued

Molecular Compounds - 2 or 3 pairs of electrons around central atom: 

Molecular Compounds - 2 or 3 pairs of electrons around central atom Each “-” between atoms represents a shared pair of electrons

Octets - 4 pairs of electrons around central atom: 

Octets - 4 pairs of electrons around central atom

Expanded Octets - 5 pairs : 

Expanded Octets - 5 pairs

Expanded Octets - 6 pairs: 

Expanded Octets - 6 pairs Square pyramidal

Covalent (polar/nonpolar) or Ionic? : 

Covalent (polar/nonpolar) or Ionic? Bond type determined by difference in electronegativity and molecular shape

Intermolecular Forces attractions between molecules: 

Intermolecular Forces attractions between molecules Van der Waals Forces Dipole interactions (picture) occurs between polar molecules Dispersion forces can occur at any moment between polar or even nonpolar

Intermolecular Forces - attractions between molecules: 

Intermolecular Forces - attractions between molecules Hydrogen bonds Strongest intermolecular attraction Occurs between the hydrogen atom of one molecule and a very electronegative (O, N, or F) atom in another molecule

How to Download PowerPoint http://www.bb.misd.net: 

How to Download PowerPoint http://www.bb.misd.net Click on the Login button 3. Click on Patti Smith’s Chemistry Place 2. Username & password: scioly 4. Click on the Course Document button & download what you need :)