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Covalent Bonding Gizmo Answers
Chemistry
High School - Canada
• 11High School - Canada
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Name: Ashley Maddison Date: 11/28/
Student Exploration: Covalent Bonds
Directions: Follow the instructions to go through the simulation. Respond to the questions and prompts in the orange boxes.
Vocabulary: covalent bond, diatomic molecule, Lewis diagram, molecule, noble gases, nonmetal, octet rule, shell, valence, valence electron
Prior Knowledge Questions (Do these BEFORE using the Gizmo.)
- There are eight markers in a full set, but Flora and Frank each only have seven markers. Flora is missing the red marker, and Frank is missing the blue marker.
What can they do so that each has a full set of markers?
Frank should give the red marker to Flora, and Flora should give the blue marker to Frank.
- Otto and Olivia each have six markers. Otto is missing the purple and green markers, and Olivia is missing the black and brown markers. What can they do so that each has a full set?
Otto should give the black and brown makers to Olivia, and Olivia should give the purple and green markers to Otto.
Gizmo Warm-up Just like the students described above, nonmetal atoms can share electrons 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.
- The outermost electrons in each atom are called valence electrons. How many valence electrons does
each fluorine atom have? 7 valence electrons.
- Click Pause ( ). Drag an electron from the left atom to the right atom. Click Play.
What happens? They equally share the one atom on the new shell that is formed.
- Click Pause , drag an electron from the right atom to the left, and then click Play.
What happens now? They continue to spiral around both atoms, but now there are two electrons on the shell.
Activity A:
Sharing electrons
Get the Gizmo ready:
● Click Reset. ● Select Hydrogen.
Introduction: The electrons that orbit the nucleus of an atom are arranged into shells. The first shell contains up to two electrons and the second contains up to eight electrons. Most elements are stable when they have eight valence electrons—a rule of thumb known as the octet rule. (Elements with less than five electrons are stable with two valence electrons.)
Question: What happens when atoms share electrons?
- Predict: Each hydrogen atom has one valence electron, but it needs two electrons to be stable. How can both hydrogen atoms each achieve a stable configuration?
Since they both need two to achieve a stable configuration, the remaining electrons can bond to one another so each atom shares them.
- 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! Because the molecule has two atoms, it is a diatomic molecule. Click the camera ( ) icon to take a snapshot of your completed molecule. Right-click the image, and click Copy Image. Paste the image into the document below and label the image “H 2 .”
📷
- ✏Draw a diagram: Covalent bonds are shown in Lewis diagrams. In a Lewis diagram, dots represent unshared valence electrons and dashes represent pairs of shared electrons.
Activity B:
Building molecules
Get the Gizmo ready:
● Click Reset. ● Turn off Show Lewis diagram. ● Select Oxygen.
Question: How do atoms share more than one pair of electrons?
- Observe: Like fluorine and most other elements, oxygen atoms are most stable with a full complement of eight valence electrons.
A. How many valence electrons does each oxygen atom have now? 6
\
B. How many more electrons does each oxygen atom need to be stable? 2
- Form a bond: Drag electrons back and forth until themolecule of oxygen (O 2 ) is stable. Click Check to confirm your molecule is stable. Take a snapshot and paste the image into your document (don’t forget to label it “O 2 ”).
3. O
How many pairs of shared electrons are there in a stable molecule of oxygen? 2
✏Draw a diagram: Draw a Lewis diagram of the oxygen molecule in the space below at left. To check your work, turn on Show Lewis diagram. Draw the correct diagram on the right.
Practice: Create covalent bonds and stable molecules for the remaining substances.
📷 Take a snapshot of each completed molecule and add it to your document.
📷
Oxygen O 6 2 8 Nitrogen N 5 3 8 Chlorine Cl 7 1 8 Carbon C 4 4 8
- Make a rule: If you knew the number of valence electrons in a nonmetal atom, how would you determine the valence of the element? (Hint: Ignore hydrogen for now.)
Ignoring hydrogen, you take the number 8 (full shell) and subtract it by the number of valence electrons to find the valence.
- Analyze: The first shell can hold a maximum of two electrons. How does this explain the valence of hydrogen?
Hydrogen only has one valence electron since it is in the first group and also has one valence. This makes the sum two, a full octet for hydrogen.
Apply: Selenium has six valence electrons. What is the valence of selenium? 2
Think and discuss: The last column of the periodic table contains the noble gases , elements that do not easily form chemical bonds.
Why don’t these gases tend to form chemical bonds?
They are unlikely to form chemical bonds due to the fact that they have little or no tendency to gain or lose electrons, since they have a full outer electron shell.
Covalent Bonding Gizmo Answers
Subject: Chemistry
High School - Canada
• 11
