Chapter 9 Vocab Flashcards
Ionic bonding
The idealized type of bonding based on the attraction of oppositely charged ions that arise through electron transfer between atoms with large differences in their tendencies to lose or gain electrons (typically metals and nonmetals).
Covalent bonding
The idealized bonding type that is based on localized electron-pair sharing between two atoms with little difference in their tendencies to lose or gain electrons (most commonly nonmetals).
Metallic bonding
An idealized type of bonding based on the attraction between metal ions and their delocalized valence electrons (see also electron-sea model).
Lewis electron-dot symbol
A notation in which the element symbol represents the nucleus and inner electrons and surrounding dot represent the valence electrons.
Octet rule
The observation that, when atoms bond, they often lose, gain, or share electrons to attain a filled outer level of eight electrons (or two for H and Li).
Lattice energy (ΔH°lattice)
The enthalpy change (always positive) that accompanies the separation of 1 mol of a solid ionic compound into gaseous ions.
Born-Hager cycle
A series of hypothetical steps and their enthalpy changes that converts elements to an ionic compound; it is used to calculate the lattice energy.
Coulomb’s law
A law stating that the electrostatic energy between particles A and B is directly proportional to the product of their charges and inversely proportional to the distance between them:
electrostatic energy ∝ (charge A x charge B)/distance
Ion pair
A gaseous ionic molecule, formed when an ionic compound vaporizes.
Covalent bond
A type of bond in which atoms are bonded through the sharing of electrons; the mutual attraction of the nuclei and an electron pair that holds atoms together in a molecule.
Bonding pair
(Also shared pair) An electron pair shared by two nuclei; the mutual attraction between the nuclei and the electron pair forms a covalent bond.
Lone pair
(Also unshared pair) An electron pair that is part of an atom’s valence level but not involved in covalent bonding.
Bond order
The number of electron pairs shared by two bonded atoms.
Single bond
A bond that consists of one electron pair.
Double bond
A covalent bond that consists of two bonding pairs; two atoms sharing four electrons in the form of one σ and one π bond.
Triple bond
A covalent bond that consists of three bonding pairs, two atoms sharing six electrons; one σ and two π bonds.
Bond energy (BE)
(Also bond enthalpy or bond strength) The standard enthalpy change (always > 0) accompanying the breakage of a given bond in 1 mol of gaseous molecules.
Bond length
The distance between the nuclei of two bonded atoms.
Infrared (IR) spectroscopy
An instrumental technique for determining the types of bonds in a covalent molecule by measuring the absorption of IR radiation.
Electronegativity (EN)
The relative ability of a bonded atom to attract shared electrons.
Polar covalent bond
A covalent bond in which the electron pair is shared unequally, so the bond has partially negative and partially positive poles.
Nonpolar covalent
A covalent bond between identical atoms in which the bonding pair is shared equally.
Electronegativity difference (ΔEN)
The difference in electronegativities between two bonded atoms.
Partial ionic character
An estimate of the actual charge separation in a bond (caused by the electronegativity difference of the bonded atoms) relative to complete separation.
Electron-sea model
A qualitative description of metallic bonding proposing that metal atoms pool their valence electrons in a delocalized “sea” of electrons in which the metal ions (nuclei and core electrons) are submerged in an orderly array.
Alloy
A mixture with metallic properties that consists of solid phases of two or more pure elements, a solid-solid solution, or distinct intermediate phases.
