molecular structure and bonding Flashcards
covalent bond in which two pairs of electrons are shared between two atoms
double bond
molecule that contains an odd number of electrons
free radical
molecule containing at least one main-group element that has more than eight electrons in its valence shell
hypervalent molecule
diagram showing lone pairs and bonding pairs of electrons in a molecule or an ion
Lewis structure
symbol for an element or monatomic ion that uses a dot to represent each valence electron in the element or ion
Lewis symbol
two (a pair of) valence electrons that are not used to form a covalent bond
lone pair
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
octet rule
bond in which a single pair of electrons is shared between two atoms
single bond
bond in which three pairs of electrons are shared between two atoms
triple bond
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
axial position
angle between any two covalent bonds that share a common atom
bond angle
(also, bond length) distance between the nuclei of two bonded atoms
bond distance
arrangement around a central atom of all regions of electron density (bonds, lone pairs, or unpaired electrons)
electron-pair geometry
one of the three positions in a trigonal bipyramidal geometry with 120° angles between them; the axial positions are located at a 90° angle
equatorial position
shape in which two outside groups are placed on opposite sides of a central atom
linear
structure that includes only the placement of the atoms in the molecule
molecular structure
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
octahedral
(also, dipole) molecule with an overall dipole moment
polar molecule
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
tetrahedral
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 bipyramidal
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
trigonal planar
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
valence shell electron pair repulsion (VSEPR) theory
distance between the nuclei of two bonded atoms at which the lowest potential energy is achieved
bond length
bond formed when electrons are shared between atoms
covalent bond
tendency of an atom to attract electrons in a bond to itself
electronegativity
covalent bond between atoms of different electronegativities; a covalent bond with a positive end and a negative end
polar covalent bond
(also nonpolar covalent bond) covalent bond between atoms of identical electronegativities
pure covalent bond
