Naming Rules Review
Ionic Compounds

A combination
between:
A metal and a nonmetal
 Metals are on the left
side of the
“staircase” starting at
Boron
 Electrons are
donated and
accepted

Ionic Compounds

Which ion goes first?

Cation comes first
◦ Metal
◦ Electron donor
◦ Positive ion forms

Anion
◦ Non-metal
◦ Electron acceptor
◦ Negative ion forms

E.g. Ca +2 (cation)
and Br-1 (anion)
makes CaBr2
Ionic Compounds

How to figure out
their formulas OR
What ratios elements
will combine in?

Valence shell electrons
◦ Stable octet desires
◦ Lose or gain electrons
◦ Overall neutral charge
required


Ca +2 (loses 2
electrons) and Br-1
(gains 1 electron
EACH) makes CaBr2
Ionic charge reflects
electron:proton ratio
Ionic Compounds

How to write their
names:
Use Periodic Table to
find out names from
symbols
 Drop the usual
ending from the
anion and add “-ide”
 E.g. NaBr is sodium
bromide (not
bromine)

Ionic Compounds

When to use Roman
numerals:
For cations (metals)
that have multiple
combining capacities
 E.g. Iron can donate
two or three
electrons, so we
name them:

◦ Iron (II)
◦ Iron (III)
Ionic Compounds

Where do Roman
numerals go in the
name?
AFTER the cation
(metal)
 E.g. Iron (II)
phosphide

Ionic Compounds

What is a polyatomic
ion?
A group of atoms
that behave as an
anion or cation unit
 E.g. OH
Ionic Compounds

How do polyatomic
ions change naming
rules?
The ending may not
be “-ide”, but will be
the name of the
ACTUAL polyatomic
ion
 E.g. beryllium nitrite
is Be(NO2)2

Ionic Compounds

The only polyatomic
ion to end in “ide”:
Hydroxide, OH E.g. beryllium
hydroxide is
Be(OH)2

Covalent Compounds

A combination
between:
A non-metal and a
non-metal
 Electron sharing

Covalent Compounds

How are the naming
rules different than
ionic compounds?

Names use prefixes
to indicate the
formula subscripts
◦
◦
◦
◦
◦
◦
◦
Mono- (1)
Di- (2)
Tri- (3)
Tetra- (4)
Penta- (5)
Hexa -(6)
Etc.
Covalent Compounds
E.g. Carbon
tetraflouride is CF4
 The prefix “mono-”
not always used (see
above example), but
can be useful for
differentiating
between two
compounds.

◦ E.g. Carbon monoxide
and carbon dioxide