GT CHEMISTRY

Unit: Nomenclature & Reactions

Name: ______Date: ______MOD: ______

Formulas

Directions:

1)  Read the passage below.

2)  Arrange the statements on the green cards in the envelope on the flow chart to coincide with the passage

3)  When the arrangement of the cards has been confirmed as correct, copy the statements onto the flow chart for future reference.

4)  Attempt to write the formulas for the indicated compounds.

To write the formula of a compound of which the name is known, one must first determine the charge of the cation. This can be done either by the noticing the cation’s position on the periodic table or by the presence of a Roman numeral following the cation (the Roman numeral will be the same as the charge). Second, the charge of the anion must be determined. A resource is available for this or, again, the position on the periodic table can indicate the charge. Once the charges are determined, the lowest whole number ratio of charges must be found. When this has been accomplished, write the symbol of the cation. If the cation is polyatomic and the subscript is a number other than one (2, 3, 4 etc.), the cation must be placed inside parentheses. Next, follow the same procedure for writing the anion. Finally, write the ratios determined earlier as subscripts. If one of the subscripts is a “1,” it doesn’t have to be written down. They are assumed. If parentheses were used, write the subscript outside of them.

Guided Practice

Directions:

1.  Use the flow chart, the ion chart and the ion cards to determine the formula for the compound in question.

2.  Use the ion cards after the charges have been determined. The cards are color coded and sized proportionately to illustrate the magnitude of the charge on each ion.

3.  When you have completed the assignment, return all cards to the envelope.

Compound Name

/

Formula

Calcium bromide
Potassium chloride
Aluminum oxide
Ammonium sulfide
Magnesium nitrate
Barium hydroxide
Tin (II) sulfide
Chromium (III) acetate


Writing Formulas – Flowchart


Practice

Directions: Give the formula for the compounds named below.

Name

/ Formula
Barium chloride
Potassium sulfide
Iron (II) bromide
Hydrogen bromide
Ammonium nitride
Aluminum hydroxide
Calcium nitrate
Magnesium sulfite
Zinc dichromate
Potassium permanganate
Ammonium hypochlorite
Sodium sulfate
Manganese (II) acetate
Mercury (II) fluoride
Tin (IV) idodide
Gold (II) perchlorate
Strontium carbonate
Iron (II) nitride
Iron (III) nitrate
Iron (II) nitrite

1