units 4 and 5: chemical bonding, periodic trends, molecular structure, and molecular dipoles

be able to predict how many electrons atoms needed to gain/lose in order to fill their valence orbitals

use the octet rule

predict gain or loss for elements with 1-3 valence electrons

lose electrons to achieve noble gas configuration

predict gain or loss for elements with 5-7 valence electrons

tend to gain electrons to achieve noble gas configuration

predict gain or loss for electrons with 4 valence electrons

can either gain or lose electrons, or share to achieve full valence shell

be able to write electron configurations for cations (positive)

write electron configuration of neutral, then subtract the number of electrons from the charge, remove from outermost shell

be able to write electron configurations for anions (negative)

write electron configuration of neutral, add number of electrons according to the charge, add to outermost shell

be able to use lewis symbols to predict the formation of basic ion compounds (including the formula of the compound that forms)

from the lewis symbol, metals lose electrons (forming cations) and nonmetals gain electrons (form anions), determine the ratio of ions due to number of electrons lost, then write chemical formula with compound being electrically neutral

what is coulomb’s law

the electrostatic force between charged particles, directly proportional to the product of the charges and inversely proportional to the square of the distance between them

what is lattice energy

the energy required to separate one mole of an ionic compound into its gaseous ions, direct result of electrostatic interactions

how do you determine whether an ion is smaller or not

cations (positive) are smaller while anions (negative) are larger

be able to use Coulomb’s law to qualitatively compare the lattice energy of different ionic compounds

greater the charge, the higher the lattice energy. smaller ions also have higher lattice energies. compounds with higher lattice energy are harder to break apart, have higher melting points, and are less soluble

be able to name ionic compounds, including ionic compounds with polyatomic ions

always name cation or metal then anion or nonmetal

nonmetal anions end with

-ide

what are polyatomic ions

groups of atoms that act as a single charged unit (SO4+)

polyatomic ions _________ have different endings

do not

be able to describe covalent bonds and predict the circumstances which promote the formation of covalent bonds

covalent bonds are formed when atoms share electrons to achieve a more stable electron configuration (full outer shell). promoted for nonmetal-nonmetal interactions and similar electronegativity

be able to predict the change in potential energy upon bond formation

when a bond is formed, the potential energy is decreased, releasing energy, making the process exothermic

be able to use lewis structures to predict simple covalent bonds and use lewis structures to draw models of molecular compounds

covalent bonds are formed when atoms achieve an octet (lines) and molecular shape is determined using VSEPR theory

be able to use formal charges to determine which lewis structure is most plausible if multiple lewis structures are possible for a molecule

number of valence electrons (pt) - number of lone pair electrons - ½ number of bonding electrons, closest to zero with negative charges on the most electronegative atoms

be able to predict the shapes of molecular compounds using Lewis structures and VSEPR

determined from number of electron groups, bonds are two each.

how many electron groups/lone pairs/bonding pairs do linear geometries have

two

how many electron groups/long pairs/bonding pairs do bent geometries have

two bonding pairs and two lone pairs

how many electron groups/long pairs/bonding pairs do trigonal planar geometries have

three electron groups

how many electron groups/long pairs/bonding pairs do trigonal pyramidal geometries have

three bonding pairs and one lone pair

how many electron groups/long pairs/bonding pairs do tetrahedral geometries have

four electron groups

use electronegativity rules to predict if molecules possess a net dipole (polar)

if the difference is significant and the molecule is asymmetrical

be able to determine if a molecule possesses polar or non-polar covalent bonds

if the electronegativity difference is less than 0.4, the bond is non-polar. if the electronegativity difference is greater than 0.4, the bond is polar

be able to name molecular compounds

identify the elements present, and use prefixes to indicate the number of atoms of each element and change the ending of the second element’s name to -ide

prefix for one

mono (often unnecessary)

prefix for two

di-

prefix for 3

tri-

prefix for 4

tetra-

prefix for 5

penta-

prefix for 6

hexa-

prefix for 7

hepta-

prefix for 8

octa

prefix for 9

nona-

prefix for 10

deca-

be able to predict and explain the trends in atomic radius

decreases across a period and increases down a group

be able to predict and explain the trends in ionic radius

increases down a group and decreases across a period

be able to predict and explain the trends in ionization energy

increases across a period and decreases down a group

be able to predict and explain the trends in electronegativity

increases across a period and decreases down a group

what is hybridization

the mixing of atomic orbitals to form new hybrid orbitals that help explain molecular bonding and geometry

how many electron groups are in sp3 hybridization and what is the molecular geometry

4, tetrahedral

how many electron groups are in sp2 hybridization and what is the molecular geometry

3, trigonal planar

how many electron groups are in sp hybridization and what is the molecular geometry

2, linear

be able to draw the molecular orbital electron configuration for homonuclear diatomic molecules in the first and second period (ex. H2, O2, etc)

use molecular orbital digrams showing how atomic orbitals combine to form molecular orbitals

be able to differentiate a structural isomer from a stereoisomer

structural isomers have different connectivity or bonds in their atoms while stereoisomers have the same connectivity, but different spatial arrangement of atoms

be able to determinate if a molecule with a single central carbon atom is chiral or not

chiral if that carbon atom is bonded to 4 different groups (chiral center) and the molecule is not superimposable (placed on top of each other and appear identical) on its mirror image