Chemical Ion Flash Cards

Introduction

Learn the chemical formulas, names and charges of 50 common ions—including monatomic and polyatomic cations and anions. Two sizes of cards allow for classroom drills, individual reviews, quizzes and games.

Concepts

• Ion formulas
• Ion chanrges
• Cations and anions
• Monatomic and polyatomic ions

Background

It is important for students in an introductory chemistry class to begin learning the language of chemistry. A good way to help students recognize and read chemical names, formulas, and equations is for them to learn the common ions. Ions are atoms or groups of atoms that have a net positive or negative charge. Once students become familiar with the names and formulas for common ions, they can begin to write chemical formulas and reactions.

The ion flash cards in this kit are specially designed to help students learn ion names and formulas. Each card has an ion name on the front side and the corresponding ion formula on the back. The ion formula includes both the symbol and the charge. It is important that students become familiar with seeing the chemical symbol together with the appropriate charge.

Each set of ion flash cards consists of 22 cations and 28 anions. A cation is any atom or group of atoms with a net positive charge, such as Cu²⁺ or NH₄ ⁺. An anion is any atom or group of atoms with a net negative charge, such as O^2– or SO₄^2–. Atoms of metallic elements tend to form cations and atoms of nonmetallic elements tend to form anions.

For cations, the name of the ion is exactly the same as the name of the element. Thus a lithium atom (Li) forms a lithium cation (Li⁺) and a magnesium atom (Mg) forms a magnesium cation (Mg²⁺). The name of an anion, on the other hand, is not the same as the element name. Instead, the name of the anion ends in -ide. Thus a sulfur atom (S) forms a sulfide anion (S^2–) and a chlorine atom (Cl) forms a chloride anion (Cl^–).

The metals in Groups 1A, 2A and 3A of the periodic table lose electrons to form cations with 1+, 2+ and 3+ charges, respectively. Notice that the ionic charge is positive and is numerically equal to the group number. The transition metals, in contrast, may have more than one common ionic charge. For example, copper forms two common cations, Cu⁺ and Cu²⁺. The two metals in Group 14 or 4A of the periodic table, tin and lead, also have more than one common ionic charge, both forming a 2+ (Sn²⁺ and Pb²⁺) and a 4+ (Sn⁴⁺ and Pb⁴⁺) cation.

Two methods of naming cations with more than one common ionic charge are used. A common method for naming cations is called the Stock system. A Roman numeral in parentheses is used as part of the name of the element to indicate the numerical value of the charge. Thus the cation Cu⁺ is the copper(I) ion and is read as the “copper one” ion while Cu²⁺ is the copper(II) ion and is read as the “copper two” ion. The older, Latin-based method of naming these cations is called the Classical system. This system uses a root word with different suffixes at the end of the word. The suffix -ous is used for the name of the cation with the lower of the two ionic charges while the suffix -ic is used with the higher of the two ionic charges. Using this system, Cu⁺ is the cuprous cation and Cu²⁺ is the cupric ion. A few transition metals have only one ionic charge. The names of these cations do not have a Roman numeral. These “exceptions” include the silver cation (Ag⁺), the cadmium cation (Cd²⁺), and the zinc cation (Zn²⁺). Notice that both the Stock and the Classical systems are used on the flash cards.

All of the ions consisting of single atoms are called monatomic ions. Unlike the monatomic ions, polyatomic ions are tightly bound groups of atoms that behave as a unit and carry a charge. The nitrate anion, for instance, is composed of one nitrogen atom and three oxygen atoms. These four atoms together form the nitrate anion. The nitrate ion has a –1 charge and is written NO₃^–. Many polyatomic anions end in -ite or -ate. However, there are three important exceptions to this rule: the ammonium cation (NH₄⁺), which ends in -ium, and two anions which end in -ide, the cyanide anion (CN^–) and the hydroxide anion (OH^–).

Notice that there is a relationship between polyatomic ions for which there is an -ite/-ate pair, such as chlorite (ClO₂^–) and chlorate (ClO₃^–). The charge on each pair is the same; however, the -ite ending indicates one less oxygen atom than the -ate ending. In addition, notice hypochlorite (ClO^–), where the prefix hypo- indicates one less oxygen atom than the -ite ending and perchlorate (ClO₄^–), where the prefix per- indicates one more oxygen atom than the -ate ending.

The 50 chemical ion flash cards in this kit provide an excellent starting point for students to learn names, formulas and charges of 50 common ions. The chosen list of 50 ions is a representative list and not necessarily a complete listing of ions. If desired, additional flash cards can be made.

Materials

Procedure

There are many class and individual activities that can be performed using the ion flash cards. These cards can easily be incorporated into your drills, quizzes, and reviews. Listed below are a few ideas included to get you started.

1. With six sets of student-size flash cards, the class can be divided into six groups. Each group will have a different colored set of cards. Students may separate their cards into two piles—a cation pile and an anion pile. They may then trade one pile with another group so that each group has one color for the cations and another color for the anions. Or, using the same idea, students may separate their cards into a monatomic ion pile and a polyatomic ion pile. If students trade one pile with another group, each group has one color for the monatomic ions and another color for the polyatomic ions.
2. Drills—Basic drills using these ion flashcards can be performed in chemistry class to introduce the chapter on formulas or perhaps to review for the test, in the same way that multiplication tables were taught for years in math classes. You can test students on the ion names, formulas, or charges using the large teacher set of cards. Simply hold up a card so all students have a chance to see it and write down an answer. Then you can choose a student to say the answer, either randomly or by raise of hand, or have all students recite the answer together. Repeating this drill for just five minutes at the end of each class during the chapter on formulas will most likely help your students learn the ions.
3. Partner Drills—Same as drills in option 2 except students work in pairs or in small groups. If the class is very large, you can divide each of the six student sets of 50 cards in half so as to have 12 sets of cards. Students would then trade their cards halfway through the drill.
4. Class Quizzes—Perhaps during the last 5 or 10 minutes of class, use the flash cards to give a class quiz. You can hold up a card and have each student write the answer on their quiz sheet. Then students can grade their own quiz or, trade papers and grade a classmate’s quiz.
5. Group Quizzes—Break the class into groups of 3 or 4 students. Students can prepare for the quiz by drilling each other using the small sets of cards. After a specified amount of time, or when the group is ready, you can sit with the group and orally quiz them. Each student in the group gets a question which only that student is allowed to answer for, let’s say, two points. If that student cannot answer, then the group can help out to get one point for the question. The grading can be done using a “group-grade” method where the final grade goes to all members of the group. Hopefully this method will motivate students to both learn and teach these ions to other members of the group.
6. Individual Quizzes—Test your students’ knowledge on a noncompetitive and individual basis. You may try using individual quizzes while the rest of the class is working on an assignment, studying, or working in groups. Show a student 5 or 10 ion cards and have them orally recite the answer. The grading job is easy here because you can immediately record the score in your gradebook.
7. Formula Writing—Use these ion flash cards to help your students learn to write chemical formulas. For example, you can hold up one cation and one anion card and have students write the formula for each ion. Then you can ask students to write the chemical formula for the ionic compound which would form if the two ions were combined. Let’s say you hold up “Aluminum” and “Nitrate.” Students would write the ions Al³⁺ and NO₃^– on their paper or quiz sheet or dry-erase board. They can then write the formula Al(NO₃)₃. This activity can be extended to teach solubility rules for ionic compounds by asking if the compound formed is soluble or insoluble.
8. Home Practice—Encourage students to quiz themselves as well as each other by taking a set of ion flash cards home. Suggest that they ask their family members or friends to quiz them.
9. Game—Divide the class into groups of 2 or 3. Arrange the desks so that each small group is separated from others. Each group needs a dry-erase board or a pad of paper and something to write with. Hold up an ion flashcard (or have a student volunteer run the game) and allow all groups time to write down an answer on their boards or paper. You can use a timer or simply watch the clock and allow a specified amount of time (perhaps 15 or 30 seconds). When time is called, all groups hold up their boards or paper and a scorekeeper records a point for each group with the correct answer. The winning group is the group with the most points at the end. This game may be ideal for teachers who like review games but prefer to avoid speed games where judging who answered first can be challenging (and may possibly cause headaches).

References

Special thanks to Robert Weiss of Port Huron High School in Port Huron, MI, for providing us with the idea and activities for these Ion Flash Cards.

Also, Robert would like to thank a colleague, Jeff McCabe, for his help in developing these ion cards.