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
2 Domains, 2 Bonds, 0 Non-Bonding Pairs
Linear
Hybrid Orbitals
Element with no singly occupied orbitals in ground state can gain energy to create singly occupied orbitals to be able to bond
Bond Dipole
Formed when two atoms share electrons unequally
Dipole Moment
Produced by two equal but opposite charges separated by a distance, r
Network Solids/Covalent Crystals
Crystalline solids in which the components are connected with covalent bonds
