T
Type
I.
I Simple
Si l Ionic
I i
Since the written name for a simple ionic compound will not
tell you how many of each atom there is, the hardest part of
going from a name to a formula is coming up with the right
number of each atom in the compound. The key to doing this
is to memorize the charges of the atomic ions
+1
+2
+1
+2
+3
-3
-2
-1
1A
H
Li
8A
2A
Be
Na Mg
TransitonMetals
K
Ca
Sc
Ti
V
Rb
Sr
Y
Cs
Ba La*
Fr
Ac*
Ra
Unq Unp Unh Uns Uno Une Uun Uuu
*
He
3A
4A
5A
6A
7A
B
C
N
O
F
Ne
Al
Si
P
S
Cl
Ar
Cr
Mn
Fe
Co
Ni
Cu
Zn
Ga Ge As
Se
Br
Kr
Zr
Nb Mo
Tc
Ru
Rh
Pd
Ag
Cd
In
Sn
Sb
Te
I
Xe
Hf
Ta
Re
Os
Ir
Pt
Au
Hg
Tl
Pb
Bi
Po
At
Rn
Tb
Dy
Ho
Er
Tm
Yb
Lu
Pu Am Cm Bk
Cf
Es
Fm Md No
Lr
W
Lathanides*
Ce
Pr
Actinides**
Th
Pa
Nd Pm Sm Eu
U
Np
Gd
T
Type
I.
I Simple
Si l Ionic
I i
Since a named compound will always have no net charge,
when you add the charges of the positive ions to the charges of
the negative ions,
ions the total must be zero.
zero Your job is to is to
come up with the proper number of positive (cation) and
negative(anion) ions to make this work, and then put these
numbers into the molecular formula as subscripts after each
atom (or complex ion).
T
Type
I.
I Simple
Si l Ionic
I i
Simple Example:
Sodium chloride
Cation: Sodium
Symbol: Na
Charge +1
Anion: Chloride
Symbol: Cl
Charge –11
Molecule:
In the formula give symbol of the cation first,
first then the anion.
anion
NaCl
Sum of charges: (+1) + (-1) = 0
Net =0, compound has no net charge, formula is good!
T
Type
I.
I Simple
Si l Ionic
I i
Simple Example: Barium chloride
Cation: Barium Symbol: Ba
Charge +2
Anion: Chloride Symbol: Cl
Charge –1
Molecule:
Try 1:
BaCl
Sum of charges: (+2) + (-1) = +1
Net = +1, compound has net charge, formula is BAD!
T gett rid
To
id off the
th +1 charge
h
we needd to
t add
dd another
th chloride.
hl id
Try 2:
BaCl2
Sum of charges (+2) + 2(-1) = 0
N t = 00, compound
Net
d hhas no nett charge,
h
formula is GOOD!
T
Type
I.
I Simple
Si l Ionic
I i
Example: Magnesium nitride
Cation: Magnesium
Symbol: Mg
Charge +2
Anion: Nitride
Symbol: N
Charge –3
Molecule:
Try 1:
MgN
Sum of charges: (+2) + (-3) = -1
Net = -1, compound has net charge, formula is BAD!
N t this
Note
thi is
i a tough
t
h example.
l Play
Pl with
ith your coefficients
ffi i t
Try 2:
Mg3N2
Sum of charges: 3(+2) + 2(-3) = 0
N t = 00, compound
Net
d hhas no nett charge,
h
formula is GOOD!
T
Type
I.
I Simple
Si l Ionic
I i
Examples to try:
Lithium fluoride
Calcium oxide
Aluminum nitride
Lithium oxide
Strontium iodide
P t i
Potassium
phosphide
h hid
Rubidium nitride
T
Type
I.
I Simple
Si l Ionic
I i
Examples to try:
Lithium fluoride
LiF
Calcium oxide
CaO
Aluminum nitride
AlN
Lithium oxide
Li2O
Strontium iodide
SrI2
P t i
Potassium
phosphide
h hid
K3P
Zinc nitride
Zn3N2