Formula Writing and Naming

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Formula Writing and Naming

• By
• Pioneer High School Chemistry Teachers

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Ion combination

• How to write a formula
• Find the symbol and charge of each ion in the
  name
• Stick them together so the charges cancel out

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Ion combination

• To find the symbol and charge use
• The periodic table
• The first name in most compounds is the same as
  the element on the table.
• The second name (nonmetal) is changed to an
• ide ending so you have to look for it.
• For example,
• Sodium Na1
• Chloride Chlorine with an ide Cl-1

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Ion combination
4/-
1
2
3
3-
2-
1-
but these vary
1
2
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Ion combination

• 2. The polyatomic ions use exactly as is.

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Ion combination

• Assignment Time
• Create flash cards for every polyatomic Ion in
  table 8-6 on page 224

Nitrate
NO3-1
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Ion combination

• To stick them together
• Sodium Chloride
• Find the symbols and charges
• Na1 Cl-1
• Stick them together to add up to zero

Na1
Cl-1
1
-1
Na
Cl
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Ion combination

• To stick them together
• Magnesium Chloride
• Find the symbols and charges
• Mg2 Cl-1
• Stick them together to add up to zero

Remember to remove the charges when you combine
the symbols
Cl-1
Mg2
Cl-1
Mg
Cl2-2
Cl-1
Cl2
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Ion combination

• To stick them together
• Sodium Phosphate
• Find the symbols and charges
• Na1
• Stick them together to add up to zero

Na1
PO4-3
PO4-3
Na3PO4
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Ion combination
Use parenthesis when you have more than one of
the polyatomic ions in a formula

• To stick them together
• Ammonium Phosphate
• Find the symbols and charges
• NH41
• Stick them together to add up to zero

PO4-3
PO4-3
NH41
(NH4)3 PO4
NH41
NH41
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Ion combination

• Try combing these cations and anions
• K1 O-2
• Ca2 OH-1
• Al3 NO3-1
• NH41 S-2
• Mg2 SO4-2

• K2O
• Ca(OH)2
• Al(NO3)3
• (NH4)2S
• MgSO4

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Ion combination

• Now try the worksheets
• Formula Writing Worksheet 1
• Formula Writing Worksheet 2

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Naming a Formula

• How to name a formula
• Write down the name of each ion in the formula
• Change an elemental anion ending to ide
• Memorize the polyatomic ions
• They dont change their names

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Naming a Formula
Dont worry about the 2 It does not affect the
name.

• K2O
• K potassium
• O oxygen

Oxygen must change its name by removing some of
the name and adding -ide
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Naming a Formula

• K2O
• K potassium
• O ox

ygen
ide
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How much name do YOU remove?
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Naming a Formula

• Try naming these formulas
• NaCl
• Ba3N2
• MgSO4
• Al2O3
• (NH4)3PO4
• H2O2

• Sodium chloride
• Barium nitride
• Magnesium sulfate
• Aluminum oxide
• Ammonium phosphate
• Hydrogen peroxide

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Roman numerals

• Transition metals in the middle of the periodic
  table, vary in their charges

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Roman numerals

• The charge needs to put into the name
• For example,
• Iron(II)oxide means Fe2 and O-2 ? FeO
• Iron(III)oxide means Fe3 and O-2 ? Fe2O3

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Roman numerals

• Try writing the formulas for
• Iron(II)sulfide
• Manganese(III)carbonate
• Chromium(I)nitride
• Chromium(II)nitride
• Chromium(III)nitride
• Chromium(IV)nitride

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Roman numerals

• To write a name for a formula containing a
  transition metal, you need to figure out the
  charge to be able to write the roman numeral in
  the name

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Roman numerals

• To find the charge
• Find the charge of the anion
• Multiply by the subscript of the anion
• This is the total negative charge
• The cations cancel the total negative charge
• Divide the total charge by the subscript of the
  cation

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Roman numerals

• Try Fe2O3
• Find the charge of the anion
• Multiply by the subscript of the anion

• O is -2
• -2 x 3 6

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Roman numerals

• To find the charge
• The cations cancel the total negative charge
• Divide the total charge by the subscript of the
  cation

• To find the charge
• The cations 6
• 6 / 2 ions 3
• 3 per ion

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Roman numerals

• To find the charge
• Put the charge in the name

• To find the charge
• Iron(III)oxide

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Molecular Naming

• How do you name a covalent molecule
• Determine which prefix to use for both atoms
  according to the number in the formula
• The first atom does not receive a prefix if there
  is only 1 atom
• Change the ending of the second atom to -ide

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Molecular Naming
Table 9-1 pg 248
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Molecular Naming

• Example
• P2O5
• Diphosphorous Pentoxide
• The a at the end of the prefix is dropped when
  you have an atom w/ a vowel beginning
• Try these on pg 249 13-17

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Molecular Naming

• Example
• CO
• Carbon Monoxide
• Try these on pg 249 13-17

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Diatomic Molecules

• There are seven elements on the periodic table
  that bond with another atom of the same element
  forming a molecule.
• This occurs in nature when these molecules are
  found alone
• (not bonded w/ a different element)
• H2 N2 O2 F2 Cl2 Br2 I2
• Help! No One From Class Brought Ice Cream

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Diatomic Molecules

• Theyre easy to find on the periodic table

H
The diatomic molecules make a number seven
N
O
F
Cl
Br
I
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Diatomic Molecules

• How do you name these molecules
• Each diatomic molecule has the same name and the
  word gas added to the end.
• Ex.
• H2 Hydrogen gas
• Cl2 Chlorine gas
• Name all of the Diatomic Molecules

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Acids

• Check Ms. Julia Bermudezs notes for this section

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Acids

• Try these on pg 250 18-22

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Hydrocarbons - Alkanes

• Table 22-1 pg 700

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Hydrocarbons - Alkanes

• Check Ms. Julia Bermudezs notes or the class
  notes from the board for this section