chapter 8 Flashcards
if the electronegative is 0.5-1.7 =
polar covalent
if the electronegative is 0.4 or less =
non-polar
if the electronegative is greater tan 1.7 = …
ionic
they have high melting points -
ionic
low melting points
covalent
they conduct electricty
ionic
never conducts electricity
covalent
they rarely burn -
ionic
burn frequently -
covalent
hard and brittle -
ionic
wide variety of textures -
covalent
form crystals -
ionic
form many different appearances -
covalent
atoms in covalent compounds …… electrons -
share
step 1 for drawing lewis dot diagram for covalent compoundds:
add up the # of valence electrons
step 2 for drawing lewis dot diagram for covalent compoundds:
least electronegative in middle
step 3 for drawing lewis dot diagram for covalent compoundds:
place a pair of electrons between pair of atoms
step 4 for drawing lewis dot diagram for covalent compoundds:
put rest of electrons around atoms
step 5 for drawing lewis dot diagram for covalent compoundds:
make sure there are 8 electrons for each atom
covalent bonds: moles can be ________ & __________
polar and non polar
molecules polarity is determined by ..
polarity of bond
geometry
if a bond is polar, then its electrons spend more time at one end of the _______ than the other
bond
if a molecule is polar, then its electrons spend more time at one end of the _______ than the other -
molecule
if all bonds = nonpolar, then molecule = ____________
non-polar
if the bonds are polar, the geometry of the molecule helps determine ________
polarity
VSEPR
valence shell electron pair repulsion
when bonded, electron pairs will move as far away from each other as possible
VSEPR Theory =
2 atoms bonded to center of atom - 0 lone pairs ==
linear
3 atoms bonded to center of atom - 0 lone pairs ==
trigonal planar
4 atoms bonded to center atom - 0 lone pairs ==
tetrahedral
3 atoms bonded ; 1 lone pair ==
ex. NH3
trigonal pyramid
2 atoms bonded ; 2 unshared pairs
ex. H2O
bent
if polar bond ….
electrons spend more time at one end of the bond
if polar molecule …
then electrons spend more time at one end of the molecule than the other
how to decide if a molecule is polar or not …
look @ the direction of the arrows - if they all point to one end of molecule then it is polar
define VESPR
electron pairs will move far away from each other as posible