Unit 9 (chapter 12) Flashcards
bond
what holds atoms together
bent
type of bond shape with 2 ligands and 2 lone pairs
bond angle
angle between ligands
bond energy
energy used to create or break a bond.
- during bond formation, energy is released, meaning it’s exothermic
- during bond breaking energy is absorbed, meaning it’s endothermic
bonding pair
electrons that are shared between atoms in a bond (opposite of lone pair, which aren’t shared)
covalent bond
- nonpolar
- molecules
- both nonmetals
- sharing electrons equally, between nuclei, overlap of orbitals
- electronegativity difference of 0, electronically symmetric
- usually 2 of the same atom
dipole moment
aka property of polar molecule (synonyms)
double bond
two bonds (4 electrons) shared between atoms
electronegativity
the tendency of an atom participating in a covalent bond to attract the bonding electrons
geometry
the three-dimensional arrangement of the atoms and chemical bonds in a molecule
isomers
One of two or more compounds that have the same chemical formula but different arrangements of the atoms within the molecules
ionic bond
- transfer of electron(s)
- between metal and nonmetal. metal becomes cation and goes down in energy, nonmetal becomes anion and goes up in energy
- must be close together, touching
- electronegativity difference of >1.7
lewis dot structure
for molecules
lewis dot symbol
for single atoms
linear
2 ligands, 0 lone pairs
lone pair
pair of electrons on molecule that is only connected to central atom
nonpolar molecule
molecules comprised with atoms that have the same electronegativity
polar covalent bond
- between two nonmetals
- electronegativity difference 0<x<1.7
- partial charges
- different atoms
polar molecule
molecule with atoms of different electronegativities. covalent
octet rule
atoms will gain/lose/share electrons to get to 8 (except B that wants 6)
resonance
- a condition when more than one lewis structure can be/has to be drawn for a particular molecule or polyatomic
- atoms do not move; e- pairs changes from long to bonding pairs
- the actual electronic structure does not actually match any one individual lewis structure, but rather is the average of all of them
resonance structure
- a condition when more than one lewis structure can be/has to be drawn for a particular molecule or polyatomic ion
- atoms do not move; e- pairs change form lone to bonding pairs
- the actual electronic structure does not match any one individual lewis structure, but rather is the average of them all
tetrahedral
4 ligands, 0 lone pairs
trigonal planar
3 ligands, 0 lone pairs
trigonal pyramidal
3 ligands, 1 lone pair
triple bond
3 bonds (6 electrons) shared between atoms
valence electron
electrons in the outermost shell of an atom
valence shell electron pair repulsion theory (VESPR theory)
a model used to predict 3-D molecular geometry based on the number of valence shell electron bond pairs among the atoms in a molecule or ion
to determine if an atom has a dipole moment
1.) Does the molecule have any polar bonds (bonds with an electronegativity difference greater than 0)
if no, the molecule cannot be polar. If yes, go to 2
2.) Are the bonds symmetrically or asymmetrically aligned in 3D?
symmetric: the polar bonds cancel and molecule is not polar
asymmetric: polar bonds don’t cancel, therefore polar
polarity in linear
identical ligands are nonpolar
nonidentical ligands are polar
polarity in bend
identical ligands are polar
nonidentical ligands are polar
polarity in trigonal planar
identical ligands are nonpolar
nonidentical ligands are polar
polarity in tetrahedral
identical ligands are nonpolar
nonidentical ligands are polar
polarity in pyramidal
identical ligands are polar
nonidentical ligands are polar
2 ligands, 0 lone pairs
linear
3 ligands, 0 lone pairs
trigonal planar
2 ligands, 2 lone pairs
bent
3 ligands, 1 lone pair
trigonal pyramidal
4 ligands, 0 lone pairs
tetrahedral
ligands
atoms that are not the central atom
