Chapter 8 - Bonding: General Concepts Flashcards
Bonding: General Concepts
bond energy
the energy required to break a given chemical bond
ionic compound
a compound that results when a metal reacts with a nonmetal to forma cation and an anion
E =2.718 2.31x10^-19 (Q1Q2/r) , where E is the energy of inter-action between a pair of ions, expressed in joules; r is the distance between the ion centers in nm; and Q2 and Q2 are the numerical ion charges.
bond length
the distance between the nuclei of the two atoms connected by a bond; the distance where the total energy of a diatomic molecule is minimal.
polar covalent bond
a covalent bond in which the electrons are not shared equally because one atom attracts them more strongly than the other.
electronegativity
the tendency of an atom in a molecule to attract shared electrons to itself.
dipole moment(dipolar)
a property of a molecule whose charge distribution can be represented by a center of positive charge and a center of negative charge.
isoelectronic ions
, ions containing the same number of electrons.
lattice energy
the energy change occurring when separated gaseous ions are packed together to form an ionic solid.
single bond
a bond in which one pair of electrons is shared by two atoms.
double bond
a bond in which two pairs of electrons are shared by two atoms.
triple bond
a bond in which three pairs of electrons are shared by two atoms.
localized electron (LE) model
a model that assumes that a molecule is composed of atoms that are bound together by sharing pairs of electrons using the atomic orbitals of the bound atoms.
lone pairs
an electron pair that is localized on a given atom; an electron pair not involved in bonding.
bonding pairs
an electron pair found in the space between two atoms.
lewis structure
a diagram of a molecule showing how the valence electrons are arranged among the atoms in the molecule
octet rule
the observation that atoms of nonmetals tend to form the most stable molecules when they are surrounded by eight electrons (to fill their valence orbitals).
resonance
a condition occurring when more than one valid Lewis structure can be written for a particular molecule. The actual electronic structure is not represented by any one of the Lewis structures but by the average of all of them.
formal charge
the charge assigned to an atom in a molecule or polyatomic ion derived from a specific set of rules.
molecular structure
the three-dimensional arrangement of atoms in a molecule.
valence shell electron-pair repulsion (VSEPR) mode
a model whose main postulate is that the structure around a given atom in a molecule is determined principally by minimizing electron-pair repulsions.
Types of chemical bonds
Ionic: electrons are transferred to form ions
Covalent: equal sharing of electrons
Polar covalent: unequal electron sharing
