Chemical Bonding
and
Compound Naming
Ionic Bonding
Ions are atoms that have lost or gained one or more
electrons, resulting in a positive or negative charge
Cation = a positively charged ion
Anion = a negatively charged ion
Are the following ions, cations or anions?
Chlorine ion
Magnesium ion
**
** Cl **
**
gains 1 electron
Cl1- anion
* loses 2 electrons
Mg *
Mg2+
cation
Oxygen ion
**
** O **
**
gains 2 electrons
O2anion
• Elements in the vertical column families develop the
same ionic charges:
Metals tend to lose electrons (form cations).
Non-metals tend to gain electrons (form anions).
Metal cation + Non-metal anion = ionic compound.
Naming Binary Ionic Compounds
• A binary ionic compound is a compound composed of
a metal cation and a non-metal anion.
• The first part of the name identifies the positive ion,
which is the metal cation.
• The second part of the name identifies the negative
ion, which is the non-metal anion.
• The name of the non-metal ion always ends with the
suffix –ide.
Elements in Ionic
Compound
Name of Ionic Compound
magnesium and
phosphorus
magnesium phosphide
sodium and chlorine
sodium chloride
calcium and bromine
calcium bromide
aluminum and oxygen
aluminum oxide
Writing the chemical formulas for
binary ionic compounds
1.
2.
3.
4.
5.
Write the symbols with the metal first:
Write the charge above each symbol.
Cross over the numbers, not the charges.
Never write a subscript 1.
Write the formula, reduce if possible.
aluminum oxide
• Practice:
Elements in Ionic
Compound
Ions
Name
Chemical
Formula
potassium and bromine
K1+ and Br1-
potassium bromide
KBr
magnesium and chlorine
Mg2+ and Cl1-
magnesium chloride
MgCl2
aluminum and sulphur
Al3+ and S2-
aluminum sulphide
Al2S3
calcium and oxygen
Ca2+ and O2-
calcium oxide
CaO
magnesium and bromine
Mg2+ and Br1-
magnesium bromide
MgBr2
calcium and iodine
Ca2+ and I1-
calcium iodide
CaI2
aluminum and oxygen
Al3+ and O2-
aluminum oxide
Al2O3
potassium and chlorine
K1+ and Cl1-
potassium chloride
KCl
magnesium and nitrogen
Mg2+ and N3-
magnesium nitride
Mg3N2
sodium and phosphorus
Na1+ and P3-
sodium phosphide
Na3P
Now let’s do some serious practice
Multivalent Metals
Multivalent metals have more than one ion charge listed on
the periodic table.
For example, copper can form ions with a +1 or +2 charge.
Cu1+ = copper (I) [pronounced “copper one”]
Cu2+ = copper (Il) [pronounced “copper two”]
Cu3N = Cu1+N3- = copper (I) nitride
Practice:
Chemical Formula
Name
SnS2
tin (IV) sulphide
Fe2O3
iron (III) oxide
FeF3
iron (III) fluoride
Cr3P2
chromium (II) phosphide
Ni2S3
OsC2
nickel (III) sulphide
osmium (VIII) carbide
Molecular Compounds
Molecular compounds are formed when atoms of two or
more different elements SHARE electrons
A covalent bond is formed when electrons are shared
between atoms.
for example, water (H20)
Diatomic gases
Elements that have two atoms joined by one or more
covalent bonds to form a molecule
The anagram is HOBrFINCl
• H2, O2, Br2, F2, I2, N2, Cl2
oxygen molecule
Element
Fluorine
Oxygen
Hydrogen
Chemical formula
of molecule
F2
O2
H2
# of electrons in
outer shell
7
6
1
# of electrons to
complete outer
shell
1
2
1
# of covalent
bonds formed
1
2
1
Lewis Diagram of
Molecule
What is the difference between a molecular
formula and structural formula?
A molecular formula is a chemical formula – it shows
the number of atoms of each element.
A structural formula shows the arrangement of the
atoms that make up a molecule.
water = H2O
glucose = C6H12O6
Binary molecular compounds
• Binary molecular compounds are compounds composed
of two non-metals joined by one or more covalent
bonds.
• You will be using the roman numeral system to name the
compounds.
Common examples: carbon dioxide (CO2)
carbon monoxide (CO)
ammonia (NH3)
Now let’s do Nomenclature Practice Sheet #2
Ionic Compounds with Polyatomic Ions
A polyatomic ion is an ion that is composed of more
than one type of atom.
A ternary compound is a compound composed of three
different elements.
For example: calcium hydroxide
Ca(OH)2
each molecule is composed of 1 calcium atom,
2 oxygen atoms, and 2 hydrogen atoms.
Naming compounds with polyatomic
ions follows the same rules as other
ionic compounds:
1. Write the cation 1st (e.g. calcium, Ca+2)
2. Write the anion 2nd (e.g. hydroxide, OH-)
Charge Name
Chemical Formula
cyanide
(CN) -
hydroxide
(OH ) -
nitrate
(NO3 ) -
chlorate
(ClO3 ) -
hydrogen carbonate
(HCO3 ) -
hydrogen sulphate
(HSO4 ) -
dihydrogen phosphate
(H2PO4 ) -
carbonate
(CO3 ) 2-
sulphate
(SO4 ) 2-
hydrogen phosphate
(HPO4 ) 2-
-3
phosphate
(PO4 ) 3-
+1
ammonium
(NH4 ) +
-1
-2
Practice:
Name
Chemical Formula
calcium carbonate
ammonium sulphate
CaCO3
(NH4)2SO4
magnesium phosphate
Mg3(PO4)2
potassium sulphate
K2SO4
calcium nitrate
iron (III) hydrogen sulphate
Ca(NO3)2
sodium phosphate
lithium hydroxide
cobalt(II) phosphate
Fe(HSO4)3
Na3PO4
LiOH
Co3(PO4)2
So what are all of these compounds?
sodium chloride
zinc oxide
calcium carbonate
calcium
hydroxide
So what are all of these compounds?
nitrogen dioxide
dinitrogen tetraoxide
sodium nitrite
carbon tetrachloride