Question

Write the name of each of the following ionic substances, using -ous or \(i c\) endings to indicate the charge of the cation. a. \(\mathrm{SnCl}_{2}\) b. FeO c. \(\mathrm{SnO}_{2}\) d. \(\mathrm{PbS}\) e. \(\mathrm{Co}_{2} \mathrm{~S}_{3}\) f. \(\mathrm{CrCl}_{2}\)

Short answer

The names of the ionic substances are: a. Stannous Chloride b. Ferrous Oxide c. Stannic Oxide d. Plumbous Sulfide e. Cobaltic Sulfide f. Chromous Chloride

Step-by-step solution

Identify the cation

In this compound, the cation is Sn (Tin).

Determine the charge of the cation

Since there are 2 chlorine atoms (with a -1 charge each), the charge of Sn must be +2 to balance the compound.

Name the compound using the -ous or -ic system

The compound's name will be Tin (II) Chloride or Stannous Chloride. b. FeO

Identify the cation

In this compound, the cation is Fe (Iron).

Determine the charge of the cation

Since there is 1 oxygen atom (with a -2 charge), the charge of Fe must be +2 to balance the compound.

Name the compound using the -ous or -ic system

The compound's name will be Iron (II) Oxide or Ferrous Oxide. c. \(\mathrm{SnO}_{2}\)

Identify the cation

In this compound, the cation is Sn (Tin).

Determine the charge of the cation

Since there are 2 oxygen atoms (with a -2 charge each), the charge of Sn must be +4 to balance the compound.

Name the compound using the -ous or -ic system

The compound's name will be Tin (IV) Oxide or Stannic Oxide. d. \(\mathrm{PbS}\)

Identify the cation

In this compound, the cation is Pb (Lead).

Determine the charge of the cation

Since there is 1 sulfur atom (with a -2 charge), the charge of Pb must be +2 to balance the compound.

Name the compound using the -ous or -ic system

The compound's name will be Lead (II) Sulfide or Plumbous Sulfide. e. \(\mathrm{Co}_{2} \mathrm{~S}_{3}\)

Identify the cation

In this compound, the cation is Co (Cobalt).

Determine the charge of the cation

Since there are 3 sulfur atoms (with a -2 charge each), and 2 cobalt atoms, the charge of Co must be +3 to balance the compound.

Name the compound using the -ous or -ic system

The compound's name will be Cobalt (III) Sulfide or Cobaltic Sulfide. f. \(\mathrm{CrCl}_{2}\)

Identify the cation

In this compound, the cation is Cr (Chromium).

Determine the charge of the cation

Since there are 2 chlorine atoms (with a -1 charge each), the charge of Cr must be +2 to balance the compound.

Name the compound using the -ous or -ic system

The compound's name will be Chromium (II) Chloride or Chromous Chloride.

Key concepts

Cation Charge

Understanding the cation charge is crucial in ionic compounds. The cation is the positive ion, and its charge is determined by balancing the negative charges of the anions. In a neutral compound, the total positive charge must equal the total negative charge.
For example, in FeO, the cation is Fe (iron). Oxygen typically carries a olinebreak -2 charge, so iron must have a olinebreak +2 charge to create a balanced compound. This balance ensures the overall charge of the compound is zero.

• When determining cation charges, observe the known charges of common anions (e.g., oxygen olinebreak -2, chlorine olinebreak -1).
• Use these anion charges to deduce the cation charge that results in a neutral compound.

By understanding cation charges, you can predict the formula of an ionic compound and check if it is correctly balanced.

Naming Ionic Compounds

Naming ionic compounds involves a two-part process: naming the cation and naming the anion. The cation's name is usually the same as the element, and the anion's name often ends in "-ide." However, when the cation can have multiple charges, the charge is indicated in parentheses using Roman numerals or by using the suffixes "-ous" or "-ic."
For instance:

• Tin (Sn) can have charges of olinebreak +2 or olinebreak +4. SnCl extsubscript{2} is called Tin (II) chloride, because tin here has a olinebreak +2 charge, or Stannous chloride using the modern system.
• In FeO, Fe has a charge of olinebreak +2, so it is Iron (II) oxide or Ferrous oxide.

These naming conventions help distinguish different compounds with the same elements. By following these guidelines, one can precisely communicate the chemical identity of a compound.

Chemical Formulas

Chemical formulas represent the types and numbers of atoms in a compound. They serve as a shorthand notation for depicting compound structure and composition.
A chemical formula consists of element symbols followed by subscripts that indicate the number of each type of atom in the compound. For ionic compounds:

• The formula is typically written with the cation first and the anion second, as in FeO or SnCl extsubscript{2}.
• Subscripts indicate how many ions of each type are needed to balance the overall charge.

In the example olinebreak Co extsubscript{2}S extsubscript{3}, two cobalt (Co) ions with a olinebreak +3 charge are required to balance the three sulfur (S) ions, each with a olinebreak -2 charge. Understanding chemical formulas allows for the calculation of formula mass, mole ratios, and the construction of balanced chemical equations essential in chemistry.