Materials Included In Kit

Additional Materials Required

Prelab Preparation

1. Make one copy of the Top Hands sheet and one copy of the List of Cards sheet for each student and distribute.
2. Distribute the deck of cards and bingo chips to each group.

Disposal

All materials may be saved and reused.

Lab Hints

• Enough materials are provided in this kit for 30 students working in groups of 6. All materials are reusable. This laboratory activity can reasonably be completed in one 50-minute class period.
• The instructor should become familiar with the game before student play. It would also be wise to show students samples of each of the hands from the VSEPR Hold ’Em hand ranking sheet before beginning the games. Explain that this game does not include any straights or flushes.
• Additional games may be set up and played after the initial round if desired.
• Have one student be the dealer for each group. Students who have played Texas Hold ’Em or other poker games would be the best candidates to be dealers.
• The VSEPR Hold ’Em game may also be played without betting rounds. Have students show their two cards (hole cards) face up as they receive them. After the flop (the first three dealer cards) has been shown, the player with the best hand wins. Keep track of overall wins by adding tally marks to a score sheet.
• A fewer number of students per game and a lower amount of points required to win may be used to speed up the game, if desired.
• The procedure can be modified so the winner must identify the missing cards needed to complete the four-card VSEPR set. For example, if the student wins with Lewis Structure Queen, Molecular Structure Queen and Bond Angle Queen, the student must identify the missing Molecular Geometry Queen as tetrahedral. If the student fails, the person on his left has the opportunity to identify the card. This continues until a student correctly identifies the card. The student who picks the correct card takes two blue chips from the winner.
• If two students have the same winning hand, then the student with the highest remaining card of the best five-card hand wins. If the students are still tied, the pot is split.

Answers to Questions

Covalent Bonding and Molecular Structure

Teacher Handouts

12504_Teacher1.pdf

References

Special thanks to Judie Baumwirt, Granada Hills Charter High School, Granada Hills, CA, for providing Flinn Scientific with the idea for this activity.

Introduction

Molecules have shape! The structure and shape of a molecule influences its physical and chemical properties. VSEPR theory can predict molecular geometries. Understand and reinforce the rules behind this useful theory by playing this variation on the popular card game Texas Hold ’Em.

Concepts

• Covalent bonds
• Valence electrons
• VSEPR theory

Background

Covalent bonds are defined as the net attractive forces between nonmetal atoms that share one, two or three pairs of valence electrons. According to the Valence Shell Electron Pair Repulsion (VSEPR) theory, the valence electron pairs that surround an atom repel each other due to their like negative charges. In order to minimize this repulsion, the electron pairs around the atom will usually arrange or position themselves so that they are as far apart as possible. The resulting symmetrical arrangement of electron pairs around atoms can be used to predict molecular geometry—the three-dimensional shape of a molecule. Two pairs of electrons around an atom should adopt a linear arrangement, three pairs a trigonal planar arrangement and so on.

The three-dimensional structure of a molecule is influenced by the spatial arrangement of all the electron pairs—both bonding and nonbonding—around the central atom. However, only the physical arrangement of the atoms is used to describe the resulting molecular geometry. This is best illustrated using examples. The Lewis structure of the water molecule is shown as the first example in Figure 1—there are four pairs of valence electrons around the central oxygen atom. Two pairs of electrons are involved in bonding to hydrogen atoms, while the other two electron pairs are unshared pairs. Four pairs of electrons around an atom will adopt a tetrahedral arrangement in space, as shown in the second structure in Figure 1, to be as far apart as possible. For this representation, the symbol

shows one lone pair of electrons extending behind the plane of the paper. The symbol shows one lone pair of electrons extending in front of the plane of the paper, while the symbols “— —” represent the hydrogen–oxygen bonds positioned in the plane of the paper. As a result, the two hydrogen atoms and the oxygen atom occupy a “bent” (inverted-V) arrangement. This is shown in the last structure in Figure 1. For elements in the third row and beyond in the periodic table, the atoms are allowed to exceed the four pairs of valance electrons. In these cases, the central atom can have five or six electron pairs around it.

Experiment Overview

In this activity, the VSEPR theory for predicting molecular geometry will be studied. The “VSEPR Hold ’Em” card game will be played to learn more about molecular geometry and its relationship to Lewis structures, bond angles, and unshared pairs of electrons.

Materials

Safety Precautions

Follow all normal classroom safety guidelines.

Procedure

The Shuffle

1. Assign one member of the group to be the dealer.
2. The dealer should obtain and shuffle the 44-card deck.
3. Each player should receive the following number of bingo chips—2 red, 5 green and 10 blue.
4. The blue bingo chips are worth 1 molecular point, the green bingo chips are worth 2 molecular points, and the red bingo chips are worth 10 molecular points.
5. Each player should also obtain a VSEPR Hold ’Em Hand Ranking Sheet and the List of Cards Sheet. This sheet ranks the possible winning combinations of cards from best to worst.

Starting the Game

6. The player directly to the left of the dealer should place 1 blue bingo chip in the pot (center of the table) before any cards are dealt. The next player to the left should place 2 blue bingo chips in the pot. This ensures that there’s something to play for on every hand.
7. The dealer should then deal each player two cards, face down. These are known as the “hole” cards. Do not show these cards to the other players.

Betting Begins

8. A round of betting takes place, beginning with the player to the left of the two players who placed the blue bingo chips in the pot.
9. Players can call (match the total number of bingo chips that have been added to the pot), raise (add additional bingo chips beyone the “call” amount) or fold (not play that hand) when it’s their turn to bet.

The Flop

10. After the first betting round, the dealer discards the top card of the deck. This is called “burning the card” and is done to ensure that no one accidentally sees the top card.
11. The dealer then flips the next three cards face up on the table. These cards are called “the flop.” Note: Eventually, a total of five cards will be placed face up on the table. Players can use any combination of these five cards and their own two hole cards to form the best possible five-card VSEPR Hold ’Em hand (see the VSEPR Hold ’Em Hand Ranking Sheet).
12. After the flop, another round of betting takes place, beginning with the player directly to the left of the dealer. During this and all future rounds of betting, players can check (pass), call, raise or fold when it’s their turn to bet as done in steps 8–9.

The Turn

13. The dealer burns another card and plays one more face up onto the table next to the flop cards. This fourth community card is called the turn.
14. The player to the left of the dealer begins the third round of betting.

The River

15. The dealer burns another card before placing the final card face up on the table. This last “community” card is called the “river.”

Final Betting and the Winner

16. Players can now use any combination of seven cards—the five cards and the two hole cards (known only to them)—to form the best possible four-card VSEPR Hold ’Em hand.
17. The fourth and final round of betting starts with the player to the left of the dealer.
18. After the final betting round, all players who remain in the game reveal their hands.
19. The player with the best VSEPR Hold ’Em hand wins all of the bingo chips in the pot.
20. The first player to obtain 120 molecular points wins the game.
21. After the game is over, you will answer the Post-Lab Questions.

Student Worksheet PDF

12504_Student1.pdf