Forming Cations and Anions
A metal has formed a positively charged ion
(cation).
Al → Al3+ + 3e-
A nonmetal has formed a negatively charged
ion (anion).
N + 3e- → N3-
8-1
Naming Cations and Anions
Name of cation is name of metal.
Al3+
aluminum
Name of anion is name of nonmetal slightly
changed.
N3-
nitride
8-2
.
Simple Cations and Anions
Cation
Name
Anion
Name
H+
hydrogen
H-
hydride
Li+
lithium
O2-
oxide
Na+
sodium
S2-
sulfide
Mg2+
magnesium
F-
fluoride
Ca2+
calcium
Cl-
chloride
Ag+
silver
Br-
bromide
8-3
Ionic Compounds (Main Group)
.
Formula
Name
NaCl
sodium chloride
Ca3N2
calcium nitride
KBr
potassium bromide
BaO
barium oxide
AlN
aluminum nitride
8-4
Formulas Using Main Group Elements
calcium nitride
Ca2+
3
N32
Ca3N2
cation always written first, anion second
criss-cross superscripts but not signs!
8-5
Formulas for Binary Ionic Compounds
.
Name
Formula
sodium chloride
NaCl
calcium nitride
Ca3N2
potassium bromide
KBr
barium oxide
BaO
aluminum nitride
AlN
8-6
Rules for Formula Writing
When the subscripts are 1, they are not
written.
When the subscripts are the same, they
are not written.
Signs (+/-) never appear with subscripts.
8-7
Cations of Transition Elements
A transitional metal forming a positively
charged ion (cation).
Cu → Cu+ + e-
Cu(I), cuprous
Cu → Cu2+ + 2e-
Cu(II), cupric
Fe → Fe2+ + 2e-
Fe(II), ferrous
Fe → Fe3+ + 3e-
Fe(III), ferric
8-8
Cations of Transition Elements
Element
Lower Valence
Higher Valence
chromium
Cr2+, chromous
Cr3+, chromic
tin
Sn2+, stannous
Sn4+, stannic
platinum
Pt2+, platinous
Pt4+, platinic
mercury
Hg22+, mercurous Hg2+, mercuric
gold
Au+, aurous
.
Au3+, auric
8-9
Binary Transition Ionic Compounds
.
Name
Formula
stannic chloride
SnCl4
chromous nitride
Cr3N2
auric bromide
AuBr3
cupric oxide
CuO
cuprous oxide
Cu2O
8 - 10
Binary Transition Ionic Compounds
.
Name
Formula
tin(IV) chloride
SnCl4
cromium(II) nitride
Cr3N2
gold(III) bromide
AuBr3
copper(II) oxide
CuO
copper(I) oxide
Cu2O
8 - 11
Ternary Compounds
Ternary compounds are compounds made up
of three elements.
Many ternary compounds consists of a cation
and a polyatomic ion.
A polyatomic ion is a group of atoms
covalently bonded that have a charge.
All binary compounds end in –ide but not all
compounds ending in –ide are binary!
8 - 12
Ternary Compounds
.
Formula
Name
CaSO4
calcium sulfate
Al(NO3)3
aluminum nitrate
CuSO4
copper(II) sulfate
Fe(IO3)3
iron(III) iodate
8 - 13
Ternary Compounds
.
Name
Formula
sodium sulfate
Na2SO4
mercuric nitrate
Hg(NO3)2
stannic chromate
Sn(CrO4)2
copper(II) phosphate
Cu3(PO4)2
8 - 14
Oxides
Oxides are compounds containing oxygen
with an oxidation state (valence) of -2 (O2-).
 CO, CO2, SO2
Oxygen can also react with active metals to
form peroxides (O22-)
 Na2O2 - sodium peroxide
 H2O2 - hydrogen peroxide
8 - 15
Hydrides
Metallic hydrides are ionic compounds where
hydrogen has an oxidation state of -1.
The hydride ion, H-, is isoelectronic with He.
Depending on the chemical environment,
hydrogen can behave like a halogen (a highly
electronegative element).
8 - 16
Hydrides
Hydrogen has a greater attraction for an
electron than an alkali or alkaline earth metal
to form hydrides.
 NaH, LiH, CaH2
In ammonia, NH3, hydrogen has an oxidation
number (valence) of +1 even though it is
traditionally written is the nonmetal position.
8 - 17