Ionic Compounds and Charge Determination

This video tutorial explains how to determine the charge of a cation in a compound, especially when the cation is from the d-block of the periodic table, like iron or manganese. The tutorial covers the importance of matching the total negative charge of anions with the total positive charge of cations to find the cation's charge. It includes practice problems with compounds containing iron and oxygen, manganese and sulfur, and iron and chlorine, demonstrating how to calculate the cation's charge and how to use Roman numerals in naming compounds.

Why is it important to determine the charge on a cation in ionic compounds?

• To predict the color of the compound

• To ensure the total charge is balanced

• To find the compound's density

• To determine the compound's melting point

What is the charge on oxygen when determining the charge of a cation?

• 1+

• 0

• 2-

• 3+

In the example with iron and oxygen, what is the total negative charge contributed by the oxygens?

• -2

• -4

• -6

• -8

How do you determine the charge on an individual iron atom in the example with two oxygens?

• By dividing the total negative charge by the number of iron atoms

• By multiplying the total negative charge by the number of iron atoms

• By adding the total negative charge to the number of iron atoms

• By subtracting the total negative charge from the number of iron atoms

In the manganese and sulfur example, what is the total positive charge that must be matched?

• +4

• +8

• +2

• +6

What is the charge on each manganese atom in the example with three sulfurs?

• +2

• +1

• +3

• +4

In the FeCl3 example, what is the total negative charge from the chlorines?

• -4

• -3

• -2

• -1

How is the charge on the iron atom determined in the FeCl3 example?

• By subtracting the total negative charge from the number of iron atoms

• By dividing the total negative charge by the number of iron atoms

• By multiplying the total negative charge by the number of iron atoms

• By adding the charges of the chlorines

What Roman numeral would be used in the name of the compound FeCl3?

• II

• I

• IV

• III

Why is it necessary to use Roman numerals in naming some ionic compounds?

• To indicate the number of atoms

• To denote the compound's state of matter

• To specify the charge on the cation

• To show the compound's color