Chem exam 3

resonance

situation in which one Lewis structure is

insufficient to describe the bonding in a

molecule and the average of multiple

structures is observed

ideal gas

hypothetical gas whose physical properties

are perfectly described by the gas laws

valence bond theory

model that describes the changes in the atomic

orbitals of an atom when it forms a covalent

compound

Dalton’s law of partial

pressures

total pressure of a mixture of ideal gases is

equal to the sum of the partial pressures of the

component gases

pi bond (π pi)

bond formed by side-by-side overlap of

atomic orbitals, in which the electron density

is found on opposite sides of the internuclear

axis

diffusion

movement of an atom or molecule from a

region of relatively high concentration to one

of relatively low concentration

hybridization

description of bonding that involves atomic

orbitals overlapping to form σ or π bonds,

within which pairs of electrons are shared

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

hypervalent molecule

molecule containing at least one main group

element that has more than eight electrons in

its valence shell

covalent bond

bond formed when electrons are shared

between atoms

Lewis symbol

symbol for an element or monatomic ion that

uses a dot to represent each valence electron

in the element or ion

hybrid orbital

orbital created by combining atomic orbitals

on a central atom

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

ideal gas law

relation between the pressure, volume,

amount, and temperature of a gas under

conditions derived by combination of the

simple gas laws

effusion

transfer of gaseous atoms or molecules from a

container to a vacuum through very small

openings

ionization energy

energy required to remove an electron from a

gaseous atom or ion

sigma bond (σ bond)

covalent bond formed by overlap of atomic

orbitals along the internuclear axis

electron-pair geometry

arrangement around a central atom of all

regions of electron density (bonds, lone pairs,

or unpaired electrons)

electromagnetic radiation

energy transmitted by waves that have an

electric-field component and a magnetic-field

component

ionic bond

strong electrostatic force of attraction between

cations and anions in an ionic compound