Multiple Choice
Which of the following is the correct formula for an ionic compound formed between K^+ and O^{2-} ions?
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3. Chemical Reactions
Writing Ionic Compounds
Multiple Choice
Which of the following is the correct chemical formula for cobalt(III) fluoride?
A
CoF2
B
CoF3
C
Co3F2
D
Co2F3
Verified step by step guidance1
Identify the oxidation state of cobalt in cobalt(III) fluoride. The Roman numeral III indicates that cobalt has a +3 charge, so Co is Co^{3+}.
Determine the charge of the fluoride ion. Fluoride (F) is a halide ion with a charge of -1, so F is F^{-}.
Balance the total positive and negative charges to form a neutral compound. Since cobalt is +3 and fluoride is -1, you need three fluoride ions to balance one cobalt ion.
Write the chemical formula by combining one Co^{3+} ion with three F^{-} ions, resulting in CoF_3.
Verify that the formula is electrically neutral: the total positive charge (+3) from cobalt equals the total negative charge (3 × -1 = -3) from fluoride ions.
