Ionic Bonding & NOMENCLATURE
TO REPLACE a MISSING ASSIGNMENT WORTH 100 Pts.
Why do ions form? What are they trying to achieve? (Has to do with the octet rule and charges)
An ionic bond is a bond between a (+) p___________ charged atom and a (-) n__________ charged atom.
These types of elements are the positive ions: ____________ . The negative ions are
non-___________.
Define a chemical bond:
Summary of Physical Properties of Ionic Compounds
Bond Formation
Type of Structure
Physical State (solid
liquid or gas?)
Melting Point
Solubility in Water
Electrical Conductivity
IN THIS FORMULA, THE POSITIVE METAL IS ALWAYS WRITTEN FIRST….THEN FOLLOWED BY THE
NEGATIVE NON-METAL.
The charges on the ions are determined by their position on the periodic table. Elements in groups 1,2 and 13 have
1, 2 and 3 valence electrons, so they lose their valence electron to expose their filled valence shell and become
positive ions. Elements in groups 14, usually share electrons-don’t usually become ions. Elements in groups 15, 16,
and 17 have 5, 6, and 7 valence electrons, so they gain electrons to fill their valence shell and become negative.
Memorize these oxidation numbers for the following groups of elements:
Elements in group 1 become (+1) ions, group 2 (+2), group 13 (+3), group 15 (-3), group 16 (-2), and group 17 (-1)
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Remember, group 18 is the noble gases, they have a filled valence shell, so they don’t become ions.
When ionic compounds are formed, they must form a compound that is n
. In other words: cations and
anions must be combined such that the total positive charges equal the total negative charges.
Look up the family names (groups) on the periodic table and name the charges of the elements in that group. Link to
a periodic table: http://www.ptable.com/
FAMILIES & CHARGES
Alkali metals
Alkaline earth
Boron family
Carbon family
Nitrogen family
Oxygen family
Halogens
Noble gases
+ or negative-they share
No charge, don’t become
ions
Naming Ions Examples:
Metal (Cation) keeps the name of the metal
K - Potassium
Ca-
Sr-
Nonmetal (Anion)
Br - Bromide
Cl-
O- Oxide
F-
N-
S-
-ide ending tells
you that the anion
came from a single
element from the
periodic table
Transition elements (2nd class ions) can sometimes form cations with more than one
charge.
These cations are named by including their charge as a Roman numeral in parentheses.
SO THE ROMAN NUMERAL TELLS YOU THE CHARGE OF THE
METAL !!!!
The Roman Numerals are:
I
II
III
IV
V

VI
VII
Cu+ is the Copper (I) ion, while Cu2+ is the Copper (II) ion.
VIII
IX
X
Pb(II) = ________
Co (III) = ________
LET’S PRACTICE!!! Write the formulas for the ionic compounds formed between the following elements:
REMEMBER YOU NEED TO BALANCE THE CHARGES!
1) First Step, determine the charge of each element- look at where it is in the periodic table and find the
oxidation number (page 1 of this sheet helps you with that)
2) Write that charge above the element so you know how much the charge is
2
3)
Make sure you have the same number of positive charges as negative.
Criss Cross Rule
When determining what ionic compound will be formed, you can use this rule to help you figure out the ratio of one
element to another. Each compound formed should result in a 0 charge.
Take the charge of the cation (the positive ion), and use that number as the subscript of your anion (the
negative ion). Take the charge of the anion and use that number as the subscript for your cation. The
subscript means how many of those atoms are in the formula. Ca3N2 has 3 Ca atoms and 2 N atoms.
Examples
You Try it!!!!
Al
+3
Cl-
Ca
+2
N-3
Formula is AlCl3
This Formula is Ca3 N2
We don’t write the 1 as a
subscript, it is understood that
there is one aluminum
Charges are balanced!
3 x +2(Ca) = +6
2 x -3(Na) = -6
IONS
1. Al +3 S -2
Al
+3
O-2
________________
Assembling Ionic Compounds:
FORMULA
2. Ba +2 N -3
3. Li +1 Br -1
4. Na +1 O -2
5. Ca +2 Cl
6. K
+1
-1
P -3
7. Zn +2 Cl
-1
Since we are talking about ionic compounds (METAL + NONMETAL), let’s start with that.
~*RULES FOR NAMING IONIC COMPOUNDS*~
1.
IDENTIFY THE CATION AND ANION. Most ionic compounds (and any I would ever give on a test) have two word
names. The first word in the name is the name of the cation, and the second word is the name of the anion. There is no
exception to this rule.
2.
NAME THE CATION. The cation is the easy part. Just find it on the periodic table and there you go UNLESS it is
one of the transition elements….in that case it will be specified by a roman numeral I, II, III, etc. if it is positive 1, 2,
3
3, etc.
3.
NAME THE ANION. How about anions? If the anion is only one type of atom, then the name of the anion is the same
as the name of the element EXCEPT the end of the element name is taken off and "-ide" is added to the end.
a. BUT, sometimes it will seem like there is more than one element there….So the question is: does the anion have
more than one atom? If the anion has more than one atom, like SO4 then we'd say that it's a "polyatomic ion",
meaning that the anion has more than one atom. It works like one ion, so it has to stay together in a compound
to be that ion and you don’t change the name such as Sulfate, or Nitrate. If you need more than one in the
compound, you need to write a subscript outside parentheses, such as Ca(NO 2)2 You will be given a table with
the polyatomic ions, so you don’t need to memorize them. None of the examples below will have polyatomic ions.
Ionic Compound Naming Practice: Formula to Name
Formula
Name
Potassium Oxide
K 2O
CaCl2
K 3P
Zinc Chloride
ZnCl2
CaO
Al2O3
Ionic Compound Naming Practice: Name to Formula
Name
Formula
Example: Potassium Chloride
Example: KCl
Calcium Bromide
Lithium Oxide
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