Chemistry Chapter 4-7
Octet rule
each element must fullfill 8 valence electrons
Chemical Bond
force that holds together a compound
nonmetals (blank) electrons
gain, anion
Empirical Formula
give the relative number of atoms of each element in a compound
Molecular Formula
gives actual number of atoms of each element in a compound
Electron Groups
lone pairs, single bonds, multiple bonds, single electrons
metal (blank) electrions
lose, cation
Chemical Formula
shows the elements there, # of atoms for each, metallic element first
Lewis Model
shows valence electrons represented with dots
Calculating Empirical Formula
1) Convert % to grams ex) 24.5% of something- 24.5 grams 2)Convert mass(grams) to mols 3) Divide by smallest number of moles 4)Now multiply all mole rations by the smallest mole number
Formal Charge
A ficticious charge something would have if all bonding electrons were shared equally.
Dipole Moment
Anytime there is a separation of positive and negative charges
Nonpolar Bonds
Atoms with the same EN, share electrons equally
Atomic Mass
Average mass of an atom
Ionic bond
Bond between a metal and non metal, electrons are transfered
Covalent Bond
Bond between two or more nonmetals, electrons are shared, results in molecular compounds
Molecular Compound
Composed of two ore more nonmetals
(0-0.4) En
Covalent Bond
Common Unit used for dipole moments
Debye (D)
Calculating Molecular Formula
Empirical formula x n ex) CH2O= CnH2nOn n=molar mass/empirical molar mass
VESPR
Idea that electron groups repel one another through coulombic forces
(2.0+) En
Ionic Bond
Five basic arrangements of electron groups
Linear, Trigonal Planar, Tetrahedral, Bipyramidal, Octahedral
Calculating a Dipole Moment
Magnitude of Charge (Q) x Distance between the charges (d)
Formula Mass
Mass of all atoms in formula added together
Calculating Percent Ionic Character
Measure of dipole moment of bond/Dipole moment if electron were transfered ****100
Odd-Electron Species
Molecules or ions with an odd number of electrons
Incomplete Octets
Molecules or ions with fewer than eight electrons, mostly metalloids an H atoms
Expanded Octets
Molecules or ions with more than eight electrons
(0.4-2.0) En
Polar Covalent Bond
Resonance Structure
Same skeletal formula, but different electron arrangement
Electronegativity
The ability of an atom to attract bonding electrons to itself, the larger the difference in EN, the more polar the bond.
Bond Angles
The character angels in the shapes
Percent Ionic Character
The ratio of a bond's actual dipole moment to the dipole moment it would have if the electron were to be completely transfer from one atom to another
Calculating Molar Mass
The sum of the atomic masses ex)SO= 32+16
Calculating Percent Composition
Used to find how much in % of an atom there is in a compound (n)x molar mass of element//// molar mass of compound
Structural formula
Uses lines to represent covalent bonds and molecular geometry.
Resonance
When two or more valid Lewis Structures can be drawn for the same compound
Lewis Structure: Lone Pair
a pair only associated with one atom and not bonding
Lewis Structure: Bonding Pair
a shared pair of electrons
