Test 1 Flashcards
All conventional ionic compounds have the following properties
- crystals of ionic compounds are hard and brittle
- ionic compounds have high melting points
- when heated to molten state, ionic compounds conduct electricity
- many ionic compounds dissolve in high-polarity solvents
(T/F) The conversion of many atoms to ions results in a significant change in size.
True
If the cation has multiple charge, then the ionic radius becomes ______.
smaller
If the anion has multiple charge, then the ionic radius becomes _______.
larger
(T/F) It is generally true that metal cations are smaller than nonmetal anions.
True
Both anions and cations increase in radius _____ down a group.
down
The ______ the ion, the shorter the interionic distance; hence the stronger the ________ attraction and the ______ the melting point.
smaller, electrostatic, higher
The ______ the charge, the higher the melting point.
higher
A cation will be more ______ if it is small and highly positively charged.
polarizing
An anion will be more easily polarized if its _______ and highly negatively charged.
large
Polarization is favored by ________ that do not have noble gas configurations.
cations
As cation charge _______ the probability of covalent behavior increases.
increases
Melting points of ________ are larger than melting points of _______.
ionic compounds
small covalent compounds
+1
ionic, except some lithium compounds
+2
ionic, except some magnesium and beryllium compounds
+3
usually covalent
+4, +5
usually covalent
+6
covalent
+7, +8
covalent
(T/F) Ions try to surround themselves with as many ions of the opposite charge as possible and as closely as possible.
True
r+/r- = 0.732 to 0.9999
Cubic
CN = 8
r+/r- = 0.414 to 0.732
Octahedral
CN = 6
r+/r- = 0.225 to 0.414
Tetrahedral
CN = 4
CsCl packing arrangment
- simple cubic packing of cations in a simple cubic anion array
- each unit cell contains 1 Cs and 1 Cl atom
- CN = 8
CaFl2 packing arrangement
- alternate simple cubic packing of cations in sc anion array
- CN = 8 for cation, CN = 4 for anions
Li2O packing arrangment
- cation tetrahedral CN = 4
- anion cubic CN = 8
- alternate scp of anion in sc cation array
sphalerite
1/2 tetrahedral packing of cations in a fcc anion array
CN = 4
wurtzite
1/2 tetrahedral packing of cations in a hcp anion array
CN = 4
Rutile (TiO2)
octahedral packing of anions of a distorted bcc cation array
- cation CN = 6
- anion CN = 3 (trigonal geometry)
BCC
CN = 8
2 atoms
FCC
CN = 12
4 atoms
HCP
CN = 12
6 atoms
