|
axial position
|
location in a trigonal bipyramidal geometry in which there is another atom at a 180° angle and the equatorial positions are at a 90° angle
|
|
|
|
|
|
bond angle
|
angle between any two covalent bonds that share a common atom
|
|
|
|
|
|
bond dipole moment
|
separation of charge in a bond that depends on the difference in electronegativity and the bond distance represented by partial charges or a vector
|
|
|
|
|
|
bond distance
|
(also, bond length) distance between the nuclei of two bonded atoms
|
|
|
|
|
|
bond energy
|
(also, bond dissociation energy) energy required to break a covalent bond in a gaseous substance
|
|
|
|
|
|
bond length
|
distance between the nuclei of two bonded atoms at which the lowest potential energy is achieved
|
|
|
|
|
|
Born-Haber cycle
|
thermochemical cycle relating the various energetic steps involved in the formation of an ionic solid from the relevant elements
|
|
|
|
|
|
covalent bond
|
bond formed when electrons are shared between atoms
|
|
|
|
|
|
dipole moment
|
property of a molecule that describes the separation of charge determined by the sum of the individual bond moments based on the molecular structure
|
|
|
|
|
|
double bond
|
covalent bond in which two pairs of electrons are shared between two atoms
|
|
|
|
|
|
electron-pair geometry
|
arrangement around a central atom of all regions of electron density (bonds, lone pairs, or unpaired electrons)
|
|
|
|
|
|
electronegativity
|
tendency of an atom to attract electrons in a bond to itself
|
|
|
|
|
|
equatorial position
|
one of the three positions in a trigonal bipyramidal geometry with 120° angles between them; the axial positions are located at a 90° angle
|
|
|
|
|
|
formal charge
|
charge that would result on an atom by taking the number of valence electrons on the neutral atom and subtracting the nonbonding electrons and the number of bonds (one-half of the bonding electrons)
|
|
|
|
|
|
free radical
|
molecule that contains an odd number of electrons
|
|
|
|
|
|
hypervalent molecule
|
molecule containing at least one main group element that has more than eight electrons in its valence shell
|
|
|
|
|
|
inert pair effect
|
tendency of heavy atoms to form ions in which their valence
s
electrons are not lost
|
|
|
|
|
|
ionic bond
|
strong electrostatic force of attraction between cations and anions in an ionic compound
|
|
|
|
|
|
lattice energy (Δ
H
lattice
)
|
energy required to separate one mole of an ionic solid into its component gaseous ions
|
|
|
|
|
|
Lewis structure
|
diagram showing lone pairs and bonding pairs of electrons in a molecule or an ion
|
|
|
|
|
|
Lewis symbol
|
symbol for an element or monatomic ion that uses a dot to represent each valence electron in the element or ion
|
|
|
|
|
|
linear
|
shape in which two outside groups are placed on opposite sides of a central atom
|
|
|
|
|
|
lone pair
|
two (a pair of) valence electrons that are not used to form a covalent bond
|
|
|
|
|
|
molecular structure
|
arrangement of atoms in a molecule or ion
|
|
|
|
|
|
molecular structure
|
structure that includes only the placement of the atoms in the molecule
|
|
|
|
|
|
octahedral
|
shape in which six outside groups are placed around a central atom such that a three-dimensional shape is generated with four groups forming a square and the other two forming the apex of two pyramids, one above and one below the square plane
|
|
|
|
|
|
octet rule
|
guideline that states main group atoms will form structures in which eight valence electrons interact with each nucleus, counting bonding electrons as interacting with both atoms connected by the bond
|
|
|
|
|
|
polar covalent bond
|
covalent bond between atoms of different electronegativities; a covalent bond with a positive end and a negative end
|
|
|
|
|
|
polar molecule
|
(also, dipole) molecule with an overall dipole moment
|
|
|
|
|
|
pure covalent bond
|
(also, nonpolar covalent bond) covalent bond between atoms of identical electronegativities
|
|
|
|
|
|
resonance
|
situation in which one Lewis structure is insufficient to describe the bonding in a molecule and the average of multiple structures is observed
|
|
|
|
|
|
resonance forms
|
two or more Lewis structures that have the same arrangement of atoms but different arrangements of electrons
|
|
|
|
|
|
resonance hybrid
|
average of the resonance forms shown by the individual Lewis structures
|
|
|
|
|
|
single bond
|
bond in which a single pair of electrons is shared between two atoms
|
|
|
|
|
|
tetrahedral
|
shape in which four outside groups are placed around a central atom such that a three-dimensional shape is generated with four corners and 109.5° angles between each pair and the central atom
|
|
|
|
|
|
trigonal bipyramidal
|
shape in which five outside groups are placed around a central atom such that three form a flat triangle with 120° angles between each pair and the central atom, and the other two form the apex of two pyramids, one above and one below the triangular plane
|
|
|
|
|
|
trigonal planar
|
shape in which three outside groups are placed in a flat triangle around a central atom with 120° angles between each pair and the central atom
|
|
|
|
|
|
triple bond
|
bond in which three pairs of electrons are shared between two atoms
|
|
|
|
|
|
valence shell electron-pair repulsion theory (VSEPR)
|
theory used to predict the bond angles in a molecule based on positioning regions of high electron density as far apart as possible to minimize electrostatic repulsion
|
|
|
|
|
|
vector
|
quantity having magnitude and direction
|
|
|
|
|