Covalent Bonds

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Login to Gizmos at go-el.com and open the Covalent Bonds gizmo.

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Prior Knowledge Questions

There are ten markers in a full set, but Mrs. King and Mr. Lowe each only have nine markers. Mrs. King is missing the red marker, and Mr. Lowe is missing the blue marker.

• What can they do so that each has a full set of markers?

Prior Knowledge Questions

Mrs. Edwards and Mrs. Ambriz each have eight markers. Mrs. Edwards is missing the blue and green markers, and Mrs. Ambriz is missing the black and brown markers.

• What can they do so that each has a full set of ten?

Gizmo Warm-up

Just like the teachers described on the previous slide, nonmetal atoms can share electrons. As you will see in the Covalent Bonds Gizmo, atoms form bonds in this way.

• To begin, check that Fluorine is selected from the Select a substance menu. Click Play to see the electrons orbiting the nucleus of each atom.

Gizmo Warm-up

The outermost electrons in each atom are called valence electrons.

• How many valence electrons does each fluorine atom have?

Click Pause. Drag a valence electron from the left atom to the right atom. Click Play.

• What happens?

Click Pause, drag a valence electron from the right atom to the left, and then click Play.

• What happens now?

Introduction

The electrons that orbit the nucleus of an atom are arranged into shells of different energy levels.

• The first shell contains up to two electrons and the second contains up to eight electrons.

Most elements are unreactive, or stable, when they have eight valence electrons—a rule of thumb known as the octet rule.

• Elements with fewer than five electrons are unreactive, or stable, with two valence electrons.

Form a Bond

• Drag the electrons so that they move around both hydrogen atoms.
• Click Play to observe them in orbit, and then click Check.
• You have created a covalent bond. Congratulations, you have completed a molecule of hydrogen!

Draw a Diagram

Covalent bonds are shown in Cross-and-Dot Diagrams and in Lewis Structure Diagrams.

• In a Lewis diagram, dots represent unshared valence electrons and dashes represent pairs of shared electrons.

Turn on Show Lewis diagram. What is the Lewis diagram for hydrogen, H₂? Draw it on the whiteboard.

Form a Bond

• Select Fluorine and turn on Highlight shared electrons.
• Create a molecule of fluorine, F₂.
• What is the Lewis Structure Diagram for fluorine, F₂? Draw it on the whiteboard.

Complete the Covalent Bonds Gizmo on your own.

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Only use the “Show Lewis Diagram” to check the work you did on your own. Honor code.

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You may use the Ball and Stick Model Kits as you work.

When you are finished, please arrange your kit like the image below: