Nomenclature
Ionic Compounds
Learning Goals
• We are learning to
– Name ionic compounds
– Understand the charges of ions in ionic
compounds
– Use what we know
about ionic charge to
determine chemical
formulas
– Name ionic compounds containing polyatomic
ions
Ionic Compounds
Recall:
• An ionic compound is formed from one or
more positively charged ions and one or more
negatively charged ions
• In ionic bonding, electrons are transferred
from one atom to another.
• The oppositely charged ions are attracted to
each other by electrostatic forces, which are
the basis of the ionic bond.
Ionic Bonding
• Metals lose electrons, become positively
charged
– sodium, potassium, magnesium, calcium
• Non-metals gain electrons, become negatively
charged
– chlorine, silicon, oxygen, sulphur
• The result of bonding is a compound that has
an overall neutral charge
Drawing Chemical Symbols
• When a sodium atom loses one electron and
becomes a positively charged ion it is symbolized
as: Na+ to indicate a charge of +1
– When more than one electron is exchanged the number
is placed before the charge.
– sulfur gains 2 electrons is symbolized as S2-
• What about the following elements?
–
–
–
–
chlorine gains 1 electron
calcium loses 2 electrons
oxygen gains 2 electrons
aluminum loses 3 electrons
Ionic Formula
• The formula of an ionic compound is derived by
combining ions such that a neutral compound is
created
• Let’s try some examples:
– calcium and chlorine
– magnesium and oxygen
– lithium and bromine
– magnesium and nitrogen
Naming Ionic Compounds
1. Name the metal ion first – same as element name
•
In KBr the name of the K+ ion is potassium.
2. Name the non-metal ion second. When non-metal
becomes a negative ion, the ending of its name
changes to “ide”
•
A bromine atom gains an electron to become a bromide ion
3. Combine the names
•
The name of KBr is potassium bromide
Naming Ionic Compounds
• Let’s try some examples:
– calcium and chlorine
– magnesium and oxygen
– lithium and bromine
– magnesium and nitrogen
Naming Ionic Compounds
• Some metals are able to form more than one
kind of ion
– EXAMPLES: copper, lead, iron, nickel
• Roman numerals are used to indicate ionic
charge
– EXAMPLE: There are two types of copper ions: Cu+
and Cu2+
• Copper(I) chloride: Cu+ forms the compound (CuCl)
• Copper(II) chloride: Cu2+ forms the compound (CuCl2)
Naming Ionic Compounds
• You can determine the Roman Numeral to use
in the name of a multivalent ion from the
subscripts in the compounds formula.
– EXAMPLE: CrCl3
– Chlorine holds a charge of -1 and there are 3 of
them in the chemical formula, therefore to make
the molecule neutral the chromium must have a
charge of +3.
– Name is chromium(III) chloride
Naming Ionic Compounds
• Let’s try some examples:
– FeCl2
– FeCl3
– CuN2
– Ni2O3
Exit Ticket
Please hand in before you go 
Homework
Complete the
handout