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What is a chemical formula?
It indicates the relative _________________
of each kind in an ionic compound.
Ex Al2O3 has ________________________________
It indicates the number of atoms of each
element contained in a single molecule of a
molecular compound.
Ex. C8H18 has 8 atoms of carbon and 18 atoms of
H in a molecule of octane.
There are different rules for naming and writing formulas for ionic and covalent compounds.
The compound is ionic if it is composed of a _________ and an________, or a_______ and a ________. The elements will be located on _________ sides of the periodic table. They have a high ___________________difference.
The compound is ___________ (or molecular) if both elements are nonmetals.
Binary because composed of only___
elements.
Ionic because composed of a metal
and a nonmetal.
Example ______________________
1). Write the symbol and charge for the cation.
2). Write the symbol and charge for the anion.
3). ________ the oxidation numbers and
______ the charges. The oxidation number
will become the subscript for the other
element.
4). ______ the subscripts if possible. If they
are the same, they __________ completely.
5). If the subscript is ___, do not write
anything.
Write the formula for calcium iodide.
Write symbols and charges.
Criss-cross oxidation numbers, drop charges.
Cancel and take away ones.
Question: Write the formula for Magnesium
Oxide.
1) Write the symbol and charge.
2) Criss cross oxidation number and drop
charges.
3). Cancel and don’t write 1’s.
Complete page 4 and the bottom of page 5 of
formula writing packet.
If a compound consists of a metal and a
nonmetal, we use the name of the first
element (always the cation) followed by the
second element (always the anion). For the
anion only, drop the last syllable and add
________. Subscripts are not included in
the name.
Examples: CaO:
LiCl:
K2S:
Some elements, such
as______________________, form 2 or more
cations with different charges. To distinguish
the ions formed by such elements, scientists
use the Stock system of nomenclature. This
system uses a ______numeral to indicate the
ion’s charge. The numeral is enclosed in
parentheses and placed immediately after
the metal name.
Fe+2 is _________ and Fe+3 is _____________
Names of metals that commonly form only
one cation, do not include a Roman numeral.
CuCl2
Determine the charges of each element, by
writing ions side by side.
Backwards criss-cross to determine charge of
cation.
Name by writing name of cation , roman
numeral, name of anion with ide instead of
last syllable.
Example: Write the formula of lead(IV)
oxide.
Write symbols with charge.
Criss cross and drop signs.
Reduce and remove 1’s.
A ___________ bonded group of atoms that has
a positive or negative charge and act as a
unit is a polyatomic ion.
The prefix poly means “many”.
Most simple polyatomic ions are ________.
____________________ is the only
polyatomic cation.
Sometimes there are ______________in the
formula, so you can tell its polyatomic.
If it contains a polyatomic ion, it is ____________, so it follows the rules for naming ionic compounds.
If anion is polyatomic, ________________________. Keep it the same as is listed on the chart. Name cation then name anion.
If the cation is polyatomic and the anion is binary, name is just like before. The______ ending means the anion is not polyatomic.
1. Write the symbols for the monatomic and polyatomic ions in the compound.
2. Look up the oxidation numbers of the ions involved.
If a single atom, use the periodic table.
If roman numeral (variable oxidation number) or polyatomic, use the chart.
3. Criss cross the oxidation numbers, and drop the charges.
4. Put polyatomic ions in _________ if they have a subscript.
5. Reduce (simplify) and erase ones.
6. DO NOT ADD< SUBTRACT, MULTIPLY, OR DIVIDE. Just criss cross and reduce if necessary!
Write the formula for Lead (II) hydroxide.
1. Write the symbol and oxidation number.
2. Criss cross charges and drop signs.
3. Use parentheses if needed.
4. Reduce and drop 1’s.
Write the formula for ammonium sulfate.
1. Write the symbol and oxidation number.
2. Criss cross charges and drop signs. Use
parentheses if needed.
3. Reduce and drop 1’s
Pringles—ammonium phosphate
Bisquick—sodium hydrogen carbonate
(sodium bicarbonate)
Mac ‘n cheese-calcium phosphate
Bacon bits—sodium nitrite
Check answers using the key provided online.
www.gavirtuallearning.org
Resources
Shared—”Click here”
Science—left side
Chemistry—left side
Chemical formulas & equations—”View”
Tab 4
Gray box on right side of page---”Binary &
Ternary Compound key”
Naming: 2, 3, 4, 7,10 only
Add: WRITE FORMULA
1. plumbic oxide
2. stannous carbonate
3. aluminum nitride
4. strontium phosphate
5. gallium hydroxide
Molecular/covalent compounds are made of 2 nonmetals.
Generally, the most metallic element is written first. These elements are farther to the left in the periodic table. If both elements are in the same group, the more metallic element is closer to the bottom of the group.
The name of the second element is changed to
-ide.
Because molecular formulas can combine in many combinations, _________ are used to indicate the subscript. ____________________________________________________
Don’t use______ on _______ element.
Write the symbols for the elements in the
order that they appear in the name.
The _______indicate the number of atoms of
each element in the molecule.
The prefixes appear as ___________in the
formulas.
If there is no prefix, there is only one atom.
(_______ element only)
Remember, do not_________.
Example tetraphosphorus dichloride
Write the formula:
1. Dibromine heptasulfide
2. Selenium tetrafluoride
3. Carbon monoxide
4. Nitrogen trichloride
Name:
1. NO
2. P2O5
3. P Cl3
4. C I4
Write formulas for:
1. Zinc nitride
2. Boron trifluoride
3. Calcium hydroxide
4. Plumbic selenide 5. aluminum dichromate
Name these:
***1ST PUT I (ionic) OR C (covalent) BESIDE THE
QUESTION
FRONT LEFT COLUMN:
1—20, 25, 26
FRONT RIGHT COLUMN:
1—18, 23, 25, 26
What do I
know about
acids?
What do I
want to
know about
acids?
What have I
learned
today about
acids?
What element do ALL acids start with?
If the acid is binary use prefix “_________”
AND the suffix “_____”.
If the acid is ternary, do not use a prefix but
change the polyatomic anion
ATE=_________
ITE= __________
All will end in the word “acid”.
You must “__________________”
like you did for ionic.
Example: chromic acid
Example: hydroiodic acid
Benzoic acid
Hydrochloric acid
Cyanic acid
Chlorous acid
Carbonic acid
Hydrobromic acid
Arsenous acid
WRITE FORMULA: NAME:
1.hydrofluoric acid 1. H2 SO3
2.arsenous acid 2. H Br
3. acetic acid 3.HCl
4. hydroiodic acid 4. H2CO3
5. phosphoric acid 5. H IO4