Ionic Compounds and Their Formulas

This video tutorial explains how to write formulas for ionic compounds. It begins with an introduction to the process, emphasizing the importance of writing the cation and anion formulas separately and adjusting subscripts to balance charges. The tutorial provides detailed examples, including Rubidium Bromide, Calcium Fluoride, Ammonium Carbonate, and Aluminum Sulfate, illustrating the step-by-step process of determining the correct chemical formulas. The video also highlights the significance of using parentheses for polyatomic ions and finding the least common multiple for balancing charges.

What is the first step in writing the formula for an ionic compound?

• Combine the cation and anion directly

• Find the least common multiple of the charges

• Write the formulas for the cation and anion separately

• Adjust the subscripts to cancel charges

In the formula for Rubidium Bromide, what is the charge on the bromide ion?

• Negative one

• Positive one

• Positive two

• Negative two

What is the correct formula for rubidium bromide?

• Rb2Br2

• RbBr

• Rb2Br

• RbBr2

How many fluoride ions are needed to balance the charge of one calcium ion in calcium fluoride?

• Three

• Two

• Four

• One

What is the charge on the calcium ion in calcium fluoride?

• Negative two

• Positive two

• Negative one

• Positive one

What is the charge on the ammonium ion in ammonium carbonate?

• Positive two

• Negative two

• Positive one

• Negative one

Why are parentheses used in the formula for ammonium carbonate?

• To avoid confusion with subscripts

• To separate different elements

• To show the charge of the ion

• To indicate multiple ions

What is the least common multiple of the charges in aluminum sulfate?

• Twelve

• Eight

• Six

• Four

How many sulfate ions are needed to balance the charge of two aluminum ions in aluminum sulfate?

• One

• Two

• Three

• Four

In the formula for aluminum sulfate, what is the subscript for the sulfate ion?

• Four

• One

• Two

• Three