Chemistry Test #5, Chapter 6

Front 1

Electronegativity

Back 1

a measure of the tendency of an atom in a bond to attract more shared electron density toward itself

Front 2

Chemical bond

Back 2

a mutual electrostatic attraction between nuclei and valence electrons of different atoms, that binds the atoms together. atoms form these bonds to lower their potential energy level possible.

Front 3

Ionic bonding

Back 3

electrostatic attraction among large numbers ofCATIONS and ANIONS

Front 4

Covalent bonding

Back 4

sharing of pairs of valence electrons between two atoms

Front 5

polar covalent bond

Back 5

a covalent bond where electrons are shared unequally, so there is a separation of charge. ∆EN must be greater than 0.4. asymmetrical geometry, bond dipoles do not cancel. IMAF is dipole-dipole forces.

Front 6

non polar covalent bond

Back 6

electrons are shared equally. ∆EN must be less than 0.4. symmetric geometry, bond dipoles cancel. IMAF is london dispersion forces.

Front 7

ionic compound

Back 7

a compound made up of cations and anions

Front 8

formula unit

Back 8

a representation of the composition of the compound, showing what elements it is made up of and their relative amounts in the simplest integer ratio. example: CO2

Front 9

crystal lattice

Back 9

a structure of an ionic compound. 3d array with balanced positive and negative charges

Front 10

lattice energy

Back 10

energy released when one mole of solid ionic compound is formed from ions in the gas phase.

Front 11

mobile sea of electrons

Back 11

valence electrons move around freely while metal ions are fixed in place. explains electrical conductivity, malleability, and luster

Front 12

heat or enthalpy of vaporization

Back 12

the amount of energy (enthalpy) that must be added to a liquid substance to transform a quantity of that substance into a gas. the higher the heat of vaporization, the stronger the metallic bond.

Front 13

molecule

Back 13

neutral group of atoms, held together by covalent bonds

Front 14

molecular compound

Back 14

a compound whose simplest unit is a molecule

Front 15

chemical formula

Back 15

a representation of the composition of a compound that specifieswhich elements make it up, and the relative amounts of each

Front 16

molecular formula

Back 16

a chemical formula that states exactly how many atoms of each element are in 1 molecule

Front 17

bond length

Back 17

distance between nuclei at minimum potential energy

Front 18

bond energy

Back 18

energy released when a bond is formed, or energy required to break the bond

Front 19

octet rule

Back 19

bonded atoms must have a full valence shell (8 electrons)

Front 20

polyatomic ion

Back 20

a charged group of covalently bonded atoms

Front 21

VSEPR theory

Back 21

valence shell electron pair repulsion theory. groups of electrons in the valence shell of the central atom repel, and stay as far apart as possible. the repulsion of electron groups determines the shape of the molecule.

Front 22

AB2 molecular geometry

Back 22

linear, 180 degrees.

Front 23

AB3 molecular geometry

Back 23

trigonal planar, 120 degrees.

Front 24

AB4 molecular geometry

Back 24

tetrahedral, 109.5 degrees

Front 25

AB2E molecular geometry

Back 25

bent, 120 degrees

Front 26

AB2E2 molecular geometry

Back 26

bent, 109.5 degrees

Front 27

AB3E molecular geometry

Back 27

trigonal pyramidal, 109.5 degrees

Front 28

AB5 molecular geometry (expanded valence shell)

Back 28

trigonal bipyramidal, 120 degrees

Front 29

AB6 molecular geometry (expanded valence shell)

Back 29

octahedral, 90 degrees

Front 30

molecular polarity

Back 30

when a bond is polar, one atom attracts shared valence electrons more strongly than the other; electrons are shared unequally

Front 31

dipole-dipole forces

Back 31

strong, permanent electrostatic attractions between oppositely charged ends of adjacent molecules

Front 32

london dispersion forces

Back 32

weak, temporary electrostatic attractions between non-polar molecules, caused by random electron fluctuations.

Front 33

hydrogen bonding

Back 33

strong electrostatic attraction between a hydrogen atom bonded to nitrogen, oxygen, or fluorine and an atom with a partial negative charge on an adjacent molecule.