Download Names and Formulas

Today’s Do Now 10/14/2014

Draw the Lewis Structure of Chlorine.

Draw the Lewis Structure of Sodium.

If sodium and chlorine were to form a bond,
what type of bond would form? How do you
know?

What is the definition of electronegativity?
Ionic Bonds
It’s getting serious
By the end of the class period today
I will be able to…
 draw
Lewis Dot Diagrams representing
the transfer of electrons in ionic bonds.
 write
the chemical formulas for ionic
compounds including polyatomic ions
utilizing the criss-cross method.
For example…
Sodium Chloride
=
“-ide” means it’s just a single element
from the PT (but there can be more
than one of them)
NaCl
It’s not always simple though…
Calcium Chloride
=
CaCl
Steps to Writing Ionic Formulas
1. Write positive ion first, then the negative
2. Determine the charge on each ion
3. Crisis cross and reduce
Subscripts: Numbers below the element that indicate the
number of that element.
Let’s try one together:

Write the chemical formula for Lithium Oxide.
You try:

Write the chemical formula for Magnesium Bromide.
You try:

Write the Chemical formula for Sodium Sulfide.
You Try

Write the chemical formula for Magnesium Oxide.
Sometimes there is something called a
polyatomic ion included.

What is the formula for Calcium Chlorate?

Calcium = Ca

Chlorate?
Endings that are not “-ide”
mean you have a
polyatomic ion.
Polyatomic Ions

A group of atoms that are bonded together and
collectively act as an anion.
 Chlorate
= ClO3
Polyatomic Ions are found on the
STAAR Ref sheet:
Writing Formulas with Polyatomic Ions




Steps to writing an ionic compound:
1. Write the formulas for the ions
2. Criss cross and reduce if necessary.
3. If a subscript is written on a polyatomic ion, polyatomic
ion is placed in parentheses, and when the subscript is
one, it is not written.
Let’s do one together…

Write the formula for Calcium Nitrite.
You try…

Write the formula for Potassium Nitrate.
You try…

Write the formula for Sodium Sulfate.
You try…

Write the formula for Magnesium Phosphate.
What if there is a Transition Metal??
 The
oxidation number of the transition
metal will be written as a roman numeral
in parentheses.
 Criss-Cross!
Copper (II) chloride
Copper (III) chloride
Example:
Iron (III)
Sulfide
Example:
Manganese
(IV) Fluoride
Write the formula for…
Lead (II)
Iodide
Lead(II) Iodide
PbI2
Example:
Lithium
Carbonate
Lithium Carbonate
Li2CO3
Example:
Iron (III)
Carbonate
Iron (III) Carbonate
Fe2(CO3)3
Independent Practice
1.
2.
3.
4.
5.
6.
7.
8.
Strontium phosphide
Beryllium sulfide
Copper (III) sulfite
Titanium (II) oxide
Ammonium fluoride
Sodium nitrite
Nickel (II) sulfate
Chromium (II) nitride