Writing Chemical Formulas and Naming Compounds

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Writing Chemical Formulas and Naming Compounds
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Ions and charges

• Main groups on the periodic table
• Positive ions (cations) name of element
  followed by the word ion
• Negative ions (anions) drop the ending of the
  name and add the suffix ide. Then add the word
  ion.
• Symbols for ions symbol for the element
  followed by a superscript showing the charge.

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1. Write the symbol for the following ions

• a.      Nitride ion
• b.      Fluoride ion
• c.      Magnesium ion
• d.      Hydrogen ion

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2. Write the name for the following ions

• a.      Na
• b.      Sr2
• c.      S-2
• d.      Br

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Naming binary ionic compounds

• The positive ion (cation) is always the first one
  in the chemical formula.
• Write the name of the positive element
• Then write the name of the negative ion (drop the
  ending and add ide)
• For example sodium chloride

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Write the name for the following binary ionic
compounds

• A. LiCl
• B. Na2O
• C. CaS
• D. MgF2

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Writing the formulas forbinary ionic compounds

• Write the symbols with the charges
• Figure out how many atoms of each ion would be
  needed to balance the overall charge to zero
• Use subscripts to show how many atoms of each ion
  are necessary

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4. Write the formula for the following binary
ionic compounds.

• A. Lithium oxide
• B. Sodium fluoride
• C. Potassium chloride
• D. Magnesium sulfide

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Naming binary molecular compounds

• Use prefixes to tell how many atoms of each
  element are needed
• 1 mono-
• 2 di-
• 3 tri-
• 4 tetra-
• 5 penta-
• 6 hexa-
• 7 hepta-

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Naming binary molecular compounds

• For the first element in the formula
• No prefix is used if there is only one atom
• If the element starts with a vowel, and the
  prefix ends with an a, drop the letter a from
  the end of the prefix
• For the second element in the formula,
• Always use a prefix
• If the element starts with a vowel, and the
  prefix ends with an a, drop the letter a from
  the end of the prefix

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5. Write the name of the following binary
molecular compounds

• A. CS2
• B. SO3
• C. N2O3
• D. Si3N4

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Writing formulas for binary molecular
compounds

• Use the prefixes to determine the number of atoms
  of each element (NOT THE CHARGE).
• 1 mono-
• 2 di-
• 3 tri-
• 4 tetra-
• 5 penta-
• 6 hexa-
• 7 hepta-

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Write the formulas for the following binary
molecular compounds

• A. dihydrogen monoxide
• B. carbon tetrafluoride
• C. dinitrogen pentoxide
• D. phosphorus trichloride

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Stock System of Nomenclature

• A naming system used to name compounds that uses
  Roman Numerals to represent the positive
  oxidation state (relative charge) of an element
  when it has more than one oxidation state.

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Stock System of Nomenclature naming compounds

• Write the name of the first element
• Check the periodic table to see if it has more
  than one positive oxidation state
• If it does, use a roman numeral in parenthesis to
  show the oxidation state then write the name of
  the negative part (drop the ending and add ide)
• If it only has one oxidation state, then no roman
  numeral is necessary. Just finish by writing the
  name of the negative part (drop the ending and
  add ide).

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Name the following compounds using the stock
system of nomenclature

• A. CuCl2
• B. NiO
• C. Co2O3
• D. PCl3

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Stock System of Nomenclature writing formulas

• Write the symbol for the first element
• Use the roman numeral to write the charge or
  oxidation state of the element
• Then write the symbol for the second part with
  the negative charge (elements only ever have one
  possible negative charge).
• Balance the charges using subscripts just like
  you did before.

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8. Write the formulas for the following compounds.

• A. Chromium (III) chloride
• B. Cobalt (II) oxide
• C. Titanium (IV) sulfide
• D. Iron (II) oxide

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Polyatomic Ions

• Groups of covalently bonded atoms with a charge
• You need to memorize ten polyatomic ions
• Treated as a single unit in compounds
• NaOH sodium hydroxide
• Fe2(SO4)3 Iron (III) sulfate

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POLYATOMIC IONS to memorize
Ammonium NH4 1 Nitrate NO3 1 Nitrite NO2
1 Sulfate SO4 2 Sulfite SO3 -2
Carbonate CO3 2 Bicarbonate HCO3
1 Phosphate PO4 3 Phosphite PO3
3 Acetate C2H302 -1
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Naming and Formulas with polyatomic ions

• Use the same rules as ionic compounds and the
  stock system of nomenclature

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9. Name these compounds using the stock system of
nomenclature.

• A. NH4Cl
• B. CuSO4
• C. Ca(NO3)2
• D. Na3PO4

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10. Write the formula for these compounds using
the stock system of nomenclature

• A. Ammonium chloride
• B. Copper (II) sulfate
• C. Iron (III) sulfite
• D. Ammonium phosphate