Chemical
Names & Formulas
Water
Ammonia Methane
1
Why “Systematic Names” ?
# atomic particles
3 (p, n, e)
# elements
~120
# elements in
8
earth’s crust (99%)
# elements in all
25
living things
# compounds
>14,000,000
2
Why “Systematic Names” ?
Water
Lime
Lye
Potash
Table Salt
Laughing Gas
Baking Soda
H2O
CaO
NaOH
K2CO3
NaCl
N2O
NaHCO3
3
Atoms vs. Ions
Atom:
 neutral
 no net charge
+
 (# p = # e )
e.g. Na  11
and 11 e
+
Cl  17 p and 17 e
+
p
4
Atoms and Ions
e
e
e
e
Ion:
e atom (or group of atoms)
 has + or – charge
 has more or less e
 only the # of e change
+
+
e.g. Na  11 p and 10 e
+
Cl  17 p and 18 e
5
Atoms and Ions
Na vs.
+
Na
Very
different
and
Cl vs.
Cl
Demo: Fe vs.
+3
Fe
6
Ions
Positive charge: “cation”
+
Na
2+
Ca
3+
Al
These atoms lost electrons to
become positive ions
Negative charge: “anion”
2
2
Cl
O
SO4
These atoms gained electrons to
become negative ions.
7
Atoms vs. Ions
“free element”
atom
lose
electrons
cation
+
smaller
gain
electrons
anion
larger
8
Compounds
 Substances composed of 2
or more different atoms
HCl
NaCl
CO2
9
Chemical Formulas
 Shows the kinds and
numbers of each type of atom
in a chemical compound.
Water = H2O
two atoms of H
one atom of O
10
Compounds
Molecular
•Atoms
bonded
as a unit
•nonmetals
e.g. H2O
Ionic
•Ions held
together by +
and - charges
•metal + nonmetal
e.g. NaCl
11
Charges NOT shown
Molecular &
Ionic Compounds
12
1. Molecular Formulas
Discrete units of bonded
nonmetal atoms.
e.g H2O & CO2
“covalent”
bond
O
H
H
“structural” formula for water
13
Naming Molecular
Compounds
(bonded nonmetal atoms)
st
nd
prefix-1 atom-prefix-2 atom-ide
number
N2O5 = dinitrogen pentoxide
14
Number
1
2
3
4
5
6
7
8
9
10
Prefix
Mono
Di
Tri
Tetra
Penta
Hexa
Hepta
Octa
Nona
Deca
Note: don’t
use ‘mono’ for
the first atom.
15
Try It
CO2
N2 O
PCl3
SF6
SO3
N2O4
H2O
Dangerous
chemical
16
Ionic Formulas
Ionic compound is represented
by a formula unit, the lowest
ratio of atoms in the compound.
NaCl
“ionic” bond
+
Na
and Cl
17
Naming Ionic Compounds
(positive metal ion +
negative nonmetal ion)
First must learn ion
names and charges!
18
Monatomic Ions
(single atom ions)
Metals  form cations (+)
+2
Mg loses two e to form Mg
Nonmetals  form anions (-)
The name ends in “ide”
Cl gains one e to form Cl
Charge from Periodic Table
19
Common Monatomic Ions
+1 +2 +3
1
2
+
Li
2+
Be
+
Na
2+
Mg
+
K
2+
Ca
+
Rb
2+
Ba
13
3+
Al
-3 -2 -1
14 15
16
17 18
3N
2O
F
3P
S
2-
Cl
3As
2Se
Br
I
end in --ide
20
Monatomic Ions: Try It.
When the following elements
become ions, state:
ion name
charge
number of e lost or gained
Ca
S
P
Br
K
Al
21
Monatomic Ions:
Some metals can form
two different types of ions.
Iron:
+2
Fe
Copper:
+1
Cu
and
+3
Fe
and
+2
Cu
•See Periodic Table for charges.
22
Multiple Charges: Names
•Stock System:
“atom (charge)”
2+
Fe
is Iron(II) ion
3+
Fe
is Iron(III) ion
23
Multiple Charges: Names
•Classical System:
Latin name ending in
“ous” for lower charge
“ic” for the higher charge
2+
Fe
is Ferrous ion
3+
Fe
is Ferric ion
24
Others
Ion
+
Cu
2+
Cu
2+
Pb
4+
Pb
2+
Sn
4+
Sn
Stock
Copper(I)
Copper(II)
Lead(II)
Lead(IV)
Tin(II)
Tin(IV)
Classic
Cuprous
Cupric
Plumbous
Plumbic
Stannous
Stannic
25
Polyatomic Ions
Some atoms group together
as a unit to form an ion.
NO3
-
26
Polyatomic Ion: Charged
group of atoms acting as a unit
NO3
nitrate ion
SO4
PO4
3-
phosphate ion
2-
+
NH4
sulfate ion
ammonium ion
27
Regents Table ‘E’
Note “ite” & “ate” pairs
--ite
--ate
2-
sulfite: SO3
nitrite:
NO2
chlorite: ClO2
2-
sulfate: SO4
nitrate: NO3
chlorate: ClO3
Be able to recognize them !!!
28
Polyatomic Ions
Be careful to distinguish between
superscripts (charges) and
subscripts (number of atoms).
2sulfite: SO3
is (SO3
1S&3O
2)
-2 charge
29
Ionic Formulas
Name: cation then anion name
•Potassium chloride
+
K
Cl
KCl
Charges must “balance”
But don’t write charges!
30
Ionic Formulas
•Calcium bromide
2+
Ca
Br
CaBr2 (balance charge)
•Copper(I) sulfate
+
2Cu
SO4
Cu2SO4
31
Shortcut  “Criss Cross”
Copper(I) sulfate
+
2Cu
SO4
Cu2(SO4)1
= Cu2SO4
The charge number (not sign) of
one ion becomes the subscript of
the opposite ion.
32
Shortcut  “Criss Cross”
Calcium sulfide
2+
2Ca S
Ca2S2 = CaS (reduce)
33
Shortcut  “Criss Cross”
Iron(III) Carbonate
3+
2Fe CO3
Fe2(CO3)3
(brackets needed
for polyatomic ion
with subscript)
34
Name or Give the Formula
of That Compound!!!
Silver chloride
CuBr2
Ammonium bromide
Mg3(PO4)2
Calcium chromate
35
Ionic Compounds
Cation (+) and Anion (-)
Cation (+): usually metal ion
2+
Mg
• Monatomic: use PT, e.g
• If more than one charge, use
Roman numerials, e.g. iron (II)
+
• Polyatomic: use Table E, e.g. NH4
36
Ionic Compounds
Cation (+) and Anion (-)
Anion (-): usually nonmetal ion
• Monatomic: use top charge on PT,
e.g Br , name ends in –ide.
• Polyatomic: use Table E, most end
in –ite or –ate e.g. NO3
Name: cation then anion, no prefix
Mg(NO3)2 is magnesium nitrate
37
Ionic Compounds
Cation (+) and Anion (-)
To write formula, criss-cross:
Iron(III) Carbonate
3+
2Fe CO3
Fe2(CO3)3
38
Try Some More!!
N2O5
PCl3
AlCl3
Sodium hydrogen sulfate
SnO2
39
General Properties
Molecular Compounds
Weak “intermolecular forces”
(molecular attractions)
Low melting & boiling points
Ionic Compounds
Strong ionic attractions
High melting & boiling points
40
Naming Acids
•Acids are a special class of
+
compounds with H as the cation.
Example:
+
H with Cl
HCl(aq)
where (aq) = dissolved in water
41
Naming Acids
Acids are named
according to the anion.
1. If the anion ends in –ide,
the acid is hydro----ic acid.
Cl is chloride
HCl(aq) is hydrochloric acid
42
Naming Acids
2. If the anion ends in –ite,
the acid is ----ous acid.
2
SO3 is sulfite
H2SO3(aq) is sulfurous
acid
43
Naming Acids
3. If the anion ends in –ate,
the acid is –ic acid.
NO3 is nitrate
HNO3(aq) is nitric acid
44
Naming Acids: Try It
Name
HCN(aq)
HClO4(aq)
HClO(aq)
HCl(aq)
45
Naming Acids: Try It
Write the formula for:
 carbonic acid
 nitrous acid
Regents Table K
46
47
Summary:
Names & Formulas
•Atoms vs. ions
+
Na
Na
•Compounds:
-molecular (nonmetals)
-ionic (metal + nonmetal)
cation(+) anion(-)
48
Summary:
Names & Formulas
•Molecular compound:
-prefix-atom-prefix-atom-ide
N2O5 = dinitrogen pentoxide
49
Summary:
Ionic compounds
-know names & charges
•monatomic ions (PeriodicTable)
•transition metals
-stock system: iron(II)
•polyatomic ions: NO3
•compound name: cation+anion
50
51
Warm-up
How many p+ and e- in Ca and Ca+2?
Is Ca+2 and anion or cation?
What are the two general types of
compounds?
How do you recognize each?
52
Warm-up
Name N2F4 and NO2
53
Warm-up
Give the symbol and the name of the ion
that each element forms:
Al
P
Write the formula of the carbonate ion.
How do you know NH4NO3 is ionic even
though it has only nonmetal atoms?
54
Warm-up
1. Fill in the table:
Molecular
Ionic
Types of atoms
Name of formula
Name of bond
2. Name N2O and Al2(SO4)3.
55
Name or give formula:
gold(I) sulfate
S2Cl5
barium phosphide
Fe3(PO4)2
calcium hydrogen carbonate
56
Warm-up
Write the formula unit for
sodium sulfate.
Why can’t this formula be
reduced?
57
Is it an ion, molecule, ionic
compound, or acid?
Then name or give formula:
NH4+
S-2
-2
SO3
NaCN
SnO
PBr3
SO3
magnesium nitride
calcium carbonate
aluminum hydrogen sulfate
H2C2O4 (or Reg. H2CO3)
FeC2O4
N2O
Au2SO4
58
Warm-up
Name or write formula:
•H2SO3
•Hydroiodic acid
•N2S4
•FeSO3
59
Warm-up
Name or write formula:
•lead(IV) carbonate
•barium nitride
•CO
•SnS2
•sulfurous acid
60