Chapter 3 - Bonding and Chemical Interactions Flashcards
(21 cards)
Octet Rule
Atoms tend to bond with other atoms so that there 8 electrons in outermost shell
- Exceptions to this rule include incomplete octets, expanded octets, and compounds with an odd number of electrons
Ionic Bond
Formed via the transfer of 1 or more electrons from an element with a relatively low IE to an element with a relatively high electron affinity
- Large differences in electronegativity ( > 1.7)
- Usually between metals and nonmetals
Cation
Positively charged ion
Anion
Negatively charged ion
Crystalline lattices
Large, organized arrays of ions
Ionic compounds
- Dissociate in H20 and other polar solvents
- High melting points
Covalent bond
Formed via the sharing of electrons between 2 elements of similar electronegativities
Bond order
Refers to whether a covalent bond is a single, double, or triple bond
- As bond order increases: bond strength increases, bond energy increases, and bond length decreases
Nonpolar bonds
Result in molecules in which both atoms have exactly the same electronegativity
- < 0.5 electronegativity too
Polar bonds
There is a significant difference in electronegativities (0.5 - 1.7)
- More electronegative element takes on partial negative charge, less takes on partial positive
Coordinate covalent bonds
Single atoms provides both bonding electrons while the other atom does not contribute
Formal Charge
Exists when an atom is surrounded by more or fewer valence electrons than it has in its neutral state
Valence Shell Electron Pair Repulsion (VSEPR) theory
Predicts the 3D molecular geometry of covalently bonded molecules
Electronic geometry
Refers to the position of all electrons in a molecule
Molecular geometry
Refers to the position of only the bonding pairs of electrons
Sigma (σ) bonds
Orbits overlap head to head
Pi (π) bonds
2 parallel electron cloud densities
intermolecular forces
Electrostatic attractions between molecules
- Weaker than covalent bonds
London dispersion forces
Weakest interactions, but are present in all atoms and molecules
- Increases as size of structure increases
Dipole-dipole interactions
Occur between the oppositely charged ends of polar molecules
- Stronger than London forces
- Solid and liquid phases
Hydrogen bonds
Specialized subset of dipole-dipole interactions
- Bonded to 1 of 3 atoms: F, O, or N
