Chapter 8: Covalent Bonding Flashcards
Covalent Bonds
Atoms share eletrons
Electrostatic Interactions In Covalent Bonds
- Attractions between electrons and nuclei
- Repulsions between electrons
- Repulsions between nuclei
Energy Change When Covalent Bond Formed
Energy is released upon formation
Sigma Bonds
Come from overlap of s orbitals, and lie between atomic nuclei; single bonds and first sticks of double and triple bonds
Pi Bonds
Generally come from overlap of p orbitals, lie outside axis between atomic nuclei; extra sticks of double and triple bonds
Single Bond (# Electrons Shared, # Sticks, Relative Length, Relative Strength, # Sigma Bonds, # Pi Bonds)
2 shared electrons, 1 stick, longest length, weakest, 1 sigma bond, 0 pi bonds
Double Bond (# Electrons Shared, # Sticks, Relative Length, Relative Strength, # Sigma Bonds, # Pi Bonds)
4 shared electrons, 2 sticks, medium length, moderately strong, 1 sigma bond, 1 pi bond
Triple Bond (# Electrons Shared, # Sticks, Relative Length, Relative Strength, # Sigma Bonds, # Pi Bonds)
6 shared electrons, 3 sticks, shortest length, strongest, 1 sigma bond, 2 pi bonds
Naming Binary Compounds
- Name elements (less electronegative molecule first)
- Change last syllable to -ide
- Use greek prefixes to show # of atoms of each element except when there is just one atom of the first element
Greek Prefixes
Mono- = 1
Di- = 2
Tri- = 3
Tetra- = 4
Penta- = 5
Hexa- = 6
Hepta- = 7
Octa- = 8
Nona- = 9
Deca- = 10
Acid Nomenclature
- If anion in acid ends in -ide, change ending to -ic acid and add prefix hydro-
- If anion in acid ends in -ite, change ending to -ous acid
- If anion in acid ends in -ate, change ending to -ic acid
Valence-Shell Electron-Pair Repulsion Theory (VSEPR Theory)
Theory that uses electron pairs to determine shapes of molecules
Types Of Ions/Molecule That Do Not Follow Octet Rule
- Ions or molecules with an odd number of electrons
- Ions or molecules with less than an octet
- Ions or molecules with more than 8 variance elections (an expanded octet)
Electron Domains
Each nonbonding electron pair, single bond, double bond, or triple bond is one electron domain
Electron-Domain Geometry & Molecular Geometry
Electron-domain geometry: arrangement of all electron domains
Molecular geometry: arrangement of atoms in a molecule
Electron-domain geometry is often not the same as molecular geometry
Hybridization
Blending of orbitals of different energy to get several orbitals of the same energy
2 electron domains = sp hybridization
3 electron domains = sp^2 hybridization
4 electron domains = sp^3 hybridization
Polar Molecules
Separation of charge:
1. Must be asymmetrical
2. Must have polar bonds
Electronegativity Differences Determining Polarity
Small (<1) = Nonpolar covalent
Medium (1-2) = Polar covalent
Large (>2) = Ionic
4 Domains, 4 Bonds, 0 Non-Bonding Pairs
Tetrahedron
4 Domains, 3 Bonds, 1 Non-Bonding Pair
Trigonal Pyramid
4 Domains, 2 Bonds, 2 Non-Bonding Pairs
Bent
4 Domains, 1 Bonds, 3 Non-Bonding Pairs
Linear
3 Domains, 3 Bonds, 0 Non-Bonding Pairs
Trigonal Planar
3 Domains, 2 Bonds, 1 Non-Bonding Pair
Bent
