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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
binary acid
compound that contains hydrogen and one other element, bonded in a way that imparts acidic properties to the compound (ability to release H+ ions when dissolved in water)
binary compound
compound containing two different elements.
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 length
distance between the nuclei of two bonded atoms at which the lowest potential energy is achieved
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
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
nomenclature
system of rules for naming objects of interest
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
oxyacid
compound that contains hydrogen, oxygen, and one other element, bonded in a way that imparts acidic properties to the compound (ability to release H+ ions when dissolved in water)
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
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