Atoms want 8ve- to be stable
“happy”
Chemical Bonds / Formulas
Atoms bond to become stable or
“happy” – octet rule (full valence
shell)
 When they bond they form
compounds.
 Each compound has a special
formula
 Subscripts show how many of
each element is in the compound

FORMULAS
MgCl2
The subscript is the
number at the bottom of a
formula.
There is 1- Mg & 2 – Cl
Never use 1 as a subscript!
IONIC BOND
bond formed between
two ions by the
transfer of electrons
Ions
 Atom
that gains or loses electrons
to become stable “happy”
 Cation: loses e- to form (+)
charged ion
 Anion: gains e- to form (-)
charged ion
Formation of Ions from Metals

Ionic compounds result when metals react
with nonmetals
 Metals lose electrons to form a positive charge

Nonmetals gain electrons to form a negative
charge

Metals:
Nonmetals:
Na+
N -3
Ca+2
S -2
Al+3
Br -
IONIC BONDS
 Bonds
form from the (+) & (-)
charges.
 Form a network of ions. – very
strong bonds.
 Conduct electricity when
melted or dissolved in water.
Writing Ionic Formulas – binary
Representative metals
Calcium & oxygen
Write the metal ion
Ca +2
Write the nonmetal ion
O -2
If charges cancel – ratio
is 1:1 ( 1 of each)
CaO
Magnesium & chlorine
Write the metal ion
Mg +2
Write the nonmetal ion
Cl If charges DO NOT
cancel – drop & swap
MgCl2
Writing Ionic Formulas – binary
Transition metals

Ion charges change – an element can have
more than one ion charge

The charge is given as a ROMAN NUMERAL
 Ex: Iron (II) Fe+2 / Iron (III) Fe+3


Gold (I) Au + / Gold (III) Au+3
You will never have to memorize all the
charges each transition metal forms – the
charges will be given to you !!!!!
Practice

Magnesium & iodine

Strontium & bromine

Barium & nitrogen

Aluminum & phosphorus

Naming Ionic Formula - binary
Representative Metals
 Name the metal
 Change the ending of the

Transition Metals
 Name the metal & Include the
charge using a Roman Numeral
nonmetal to – ide
MgCl2 - magnesium chloride
AlP - aluminum phosphide
Ex: Iron (II) Fe+2 / Iron (III) Fe+3
Gold (I) Au + / Gold (III) Au+3
 Change the ending of the
Cl – chloride
F – flouride
I – iodide
P – phosphide
Br – bromide
C - carbide
Se - selenide
N – nitride
S – sulfide
O – oxide
nonmetal ending to –ide
Fe +2 Cl -
iron (II) chloride
Au + O -2
gold (I) oxide
Practice

CaBr2

FeCl3

Na3N

Ni3N

BCl3

ZnO

MgO

FeS
Ternary Ionic Bonds – contain
Polyatomic Ions
 Polyatomic
ion : a
group of (covalently)
bonded nonmetals
that form a charge.
 Act as a single ion in
an ionic bond
 Have special names
that DO NOT
CHANGE
 You
need to write
down the
polyatomic ions and
their names on a
sheet of paper and
DO NOT LOSE IT!!!
 You will use your list
on all quizzes and
tests!











Ammonium NH4+
Carbonate
Chromate
Acetate
C2H3O2Dichromate
Hypochlorite ClOOxalate
Chlorite
ClO2
Sulfate
Chlorate
ClO3Sulfite
Perchlorate ClO4Phosphite
Phosphate
Cyanide
CNPermanganate
Hydroxide
OHPeroxide
Nitrite
NO2
Nitrate
NO3Bicarbonate/Hydrogen Carbonate HCO3-
CO3-2
CrO4-2
Cr2O7-2
C2O4-2
SO4-2
SO3-2
PO3-3
PO4-3
MnO4O2-2
Writing Ionic Formulas - ternary

Write the cation – all metals (only polyatomic cation
is ammonium: NH4+ )

Write the anion – all nonmetals and polyatomic
ions

If charges cancel – 1:1 ratio

If charges DO NOT cancel – drop & swap
 You must use parenthesis if more than one
polyatomic ion is present
Practice

cesium nitrate

Iron(III) chlorite

barium sulfite

Zinc(II) nitrite

aluminum hydroxide

Gold(III) carbonate

strontium phosphate

Silver(I) phosphite

ammonium sulfide

Copper(I) acetate
Naming ionic formulas - ternary
Representative metal
 Name the cation
 Use the same name
for the polyatomic ion

If the anion is a
nonmetal – change
the ending to -ide
Transition metal
 Name the metal and include
a ROMAN NUMERAL for
the charge of the metal
 Use the same name for the
polyatomic ion

If the anion is a nonmetal –
change the ending to -ide
Group 1 - Alkali Metals
 reacts
violently with water
 VERY reactive, one valence eto lose;
 +1 cation
Alkali metals

http://www.youtube.com/watch?v=m55k
gyApYrY&safety_mode=true&persist_sa
fety_mode=1
Group 2 - Alkaline Earth
Metals
2
valence e-;
+2 cation
reactive

http://www.youtube.com/watch?v=m55k
gyApYrY&safety_mode=true&persist_sa
fety_mode=1
Transition Metals
Groups
3-12
Ions charges change –
changes properties
NOT REPRESENTATIVE!
Halogens
-Group
17
-1 ions, highly
reactive
7 valence e-
Noble Gases
Group
18
unreactive, 8 valence edo not form ions
exist as single atoms,
don’t bond - inert
COVALENT BOND
bond formed by the
sharing of electrons
Covalent Compounds
 Covalent
compounds result when
nonmetals react with nonmetals
 Both
nonmetals share their valence
electrons to be happy – Octet Rule
 Examples:

CO2
SCl2

H 2O
CH4
Naming Covalent formulas
Use prefixes to show the # of atoms of each
element in a covalent compound
 1 – mono
6 - hexa
 2 – di
7 - hepta
 3 – tri
8- octa
 4 – tetra
9 - nona
 5 – penta
10 – deca

1st element – use prefixes only of the # of atoms
is greater than 1
 2nd element – use prefixes; change ending to –
ide

Practice

CO2
carbon dioxide

N 3F 8
trinitrogen octaflouride

Se4Br9
tetraselenium nonabromide

S 7O
heptasulfur monoxide
Writing Covalent formulas
Use the prefix to identify how many of each
nonmetal atoms are in each molecule
 The prefix becomes the subscript.

 Carbon Tetrahydride
○
CH4
Disulfur Hexachloride
S2Cl6
1)
Name the following covalent compounds:
a) SiF4
b) N2S3
c) H3Br7
d) S5Br9
e) H2O
2) Write the formulas for the following covalent
compounds:
a) diboron hexahydride
b) nitrogen tribromide
c) sulfur hexachloride
d) diphosphorus pentoxide