Vocab. Chapter 8

Front 1

axial

Back 1

in the trigonal bipyramidal electron-pair geometry, the two positions directly across from each other

Front 2

bent

Back 2

the molecular geometry of a triatomic molecule or ion in which the bond angle is less than 180 degrees

Front 3

bond angle

Back 3

the angle between two atoms bonded to a central atom

Front 4

bond axis

Back 4

an imaginary line connecting the nuclei of two bonded atoms

Front 5

bond dissocitiation enthalpy

Back 5

the enthalpy change for breaking a bond in a molecule, with the reactants and products in the gas phase at standard conditions. Also called bond energy

Front 6

bond length

Back 6

the distance between the nuclei of two bonded atoms

Front 7

bond order

Back 7

the number of bonding electron pairs shared by two atoms in a molecule or polyatomic ion

Front 8

bond pair

Back 8

two electrons, shared by two atoms, that contribute to the bonding attraction between the atoms

Front 9

bond

Back 9

an interaction between atoms that holds them together by reducing the potential energy of their electrons

Front 10

bonding pair

Back 10

a pair of electrons that is shared between two atoms

Front 11

chemical bond

Back 11

an attractive force between two atoms that causes the atoms to be attached together

Front 12

coordinate covalent bond

Back 12

a bond in which both electrons in the bond were contributed by the same atom

Front 13

core electrons

Back 13

the electrons in an atoms completed set of shells

Front 14

covalent bond

Back 14

an interatomic attraction resulting from the sharing of electrons between atoms

Front 15

covalent compound

Back 15

a compound formed by atoms that are held together by only covalent bonds

Front 16

dipole-dipole attraction

Back 16

the electrostatic force between two molecules that have permanent dipole moments

Front 17

dipole moment

Back 17

a measure of the degree of charge separation in a molecule which is the product of the positive charge, Q, in electrostatic units and the distance

Front 18

double bond

Back 18

a covalent bond formed by sharing two pairs of electrons, one pair in a sigma bond and the other pair in a pi bond

Front 19

electron-pair geometry

Back 19

the geometry determined by all the bond pairs and lone pairs in the valence shell around a central atom

Front 20

electronegativity

Back 20

a measure of the ability of an atom in a molecule to attract shared electrons to itself

Front 21

electroneutrality principle

Back 21

electrons will be distributed in such a way that the charges on all atoms are as close to zero as possible

Front 22

equatorial

Back 22

in the trigonal bi-pyramidal electron-pair geometry, the three positions in a plane midway between the two axial positions

Front 23

formal charge

Back 23

the charge on an atom in a molecule or ion, which is determined by comparing the number of valence electrons in the element to the number of electrons from assigning lone pairs solely to the atom and evenly splitting bonding pairs between the atoms forming a bond

Front 24

free radical

Back 24

a neutral atom or molecule containing an unpaired electron, which is usually very reactive

Front 25

intermolecular forces

Back 25

interactions between molecules, between ions, or between molecules and ions

Front 26

ionic bond

Back 26

the electrostatic attraction between two oppositely charged ions

Front 27

isoelectronic species

Back 27

molecules or ions that have the same number of valence electrons and similar Lewis structures

Front 28

lewis electron dot symbol

Back 28

a notation for the valence electron configuration of an atom

Front 29

lewis structure

Back 29

a representation of a covalently bonded species in which a lone pair that belongs olely to one atom is represented by two dots, and a pair of electrons that is shared between two atoms as a bond is represented by a line connecting the two atoms

Front 30

linear

Back 30

the molecular geometry of a triatomic molecule or ion with a bond angle of 180 degrees

Front 31

lone pair

Back 31

a pair of valence electrons that belongs solely to one atom, and does not contribute to bonding in a covalent molecule

Front 32

molecular geometry

Back 32

the arrangement in space of a central atom and the atoms directly attached to it

Front 33

nonbonding electrons

Back 33

electrons that are not shared between atoms in a covalent species, and belong solely to one atom

Front 34

nonpolar covalent bond

Back 34

a covalent bond in which the bonding electrons are shared equally between the two bonded atoms, which has a dipole moment of zero

Front 35

octahedral

Back 35

the electron-pair geometry when six groups are connected to a central atom, and the molecular geometry when all six groups in an octahedral electron-paoir geometry are atoms

Front 36

octet

Back 36

a stable configuration of eight valence electrons in completed s and p subshells

Front 37

octet rule

Back 37

when forming bonds, atoms of main group elements gain, lose, or share electrons to achieve a stable configuration having eight valence electrons

Front 38

partial charge

Back 38

the charge on an atom in a molecule that is calculated by assuming sharing of the bonding electrons proportional to the electronegativity of the atom

Front 39

polar covalent bond

Back 39

a covalent bond in which there is unequal sharing of the bonding electron pair

Front 40

resonance hybrid

Back 40

the actual structure of a molecule or ion that exhibits resonance

Front 41

resonance structures

Back 41

the possible structure of a molecule for which more than one lewis structure can be written, differing by the number of bond pairs between a given pair of atoms

Front 42

seesaw

Back 42

the molecular geometry when four atoms and one lone pair are connected to a central atom with the trigonal bipyramidal electron-pair geometry

Front 43

single bond

Back 43

a covalent bond formed by sharing one pair of electrons in a sigma bond

Front 44

square planar

Back 44

the molecular geometry when four atoms and two lone pairs are connected to a central atom with the octahedral electron-pair geometry

Front 45

square pyramidal

Back 45

the molecular geometry when five atoms and one lone pair are connected to a central atom with the octahedral electron-pair geometry

Front 46

t-shaped

Back 46

the molecular geometry when three atoms and two lone pairs are connected to a central atom with the trigonal bipyramidal electron-pair geometry

Front 47

tetrahedral

Back 47

the electron-pair geometry having four groups connected to a central atom, and the molecular geometry when all four groups in a tetrahedral electron-pair geometry are atoms

Front 48

trigonal bipyramidal

Back 48

the electron pair geometry when five groups are connected to a central atom, and the molecular geometry when all five groups in a trigonal bipyramidal electron pair geometry are atoms

Front 49

trigonal planar

Back 49

the electron-pair geometry having three groups connected to a central atom, and the molecular geometry that results when all there groups connected to a central atom with the trigonal planar electron pair geometry are atoms

Front 50

trigonal pyramidal

Back 50

the molecular geometry when three atoms and one lone pair are connected to a central atom with the tetrahedral electron pair geometry

Front 51

triple bond

Back 51

a covalent bond formed by sharing three pairs of electrons, one pair in a sigma bond and the other two in pi bonds

Front 52

valence electrons

Back 52

the outermost and most reactive electrons of an atom

Front 53

valence shell electron pair repulsion model (VSEPR)

Back 53

a model for predicting the shapes of molecules in which structural electron pairs are arranged around each atom to minimize electron-electron repulsions by maximizing the distance between them