Concord Visualizing Bonding with e- clouds Name:____________________________Period#_______
Go to the Concord site below and click the Chemical Bonding simulator, then click run. Follow the steps
in order and answer the question below. Draw and Explain your answers.
http://mw.concord.org/modeler/index.html
You will be doing working through Parts 1, 2, 3, + Part of 4
Part 1: Introduction
1. Why are electrons important in chemistry?
Electron cloud: In atoms and molecules, the state of an electron is described using an electron cloud,
which represents how probable it is to be found at a given location. In 2009, scientists photographed
the electron clouds around a carbon atom using a field emitting microscope.
2. Draw the e- clouds shown for carbon in two different configurations
3.
Compare clouds in the sky with electron clouds. What are the similarities and what are the
differences?
Part 2: The formation of an atom
4. What happens when an electron cloud comes close to a nucleus?
5. Instructions: Click the "Run" button. With a Nucleus (positively charged)
6. Draw what the e- cloud looks like with a
7. Drag the plus sign around and observe how the
positive nucleus:
electron cloud reacts.
8. What happened when you dragged the
positive nucleus around?
9.Why?
10. Select "Neutron" and Click the "Run" button with a Neutron.
11. Draw what the e- cloud looks like with a
12.Drag the neutral nucleus around and observe
neutral nucleus:
how the electron cloud reacts.
13.What happened when your dragged the
neutral nucleus around?
14.Why?
15. Select "Negative ion" and Click the "Run" button with a negative ion.
16.Draw what the e- cloud looks like with a
17. Drag the negative around and observe how
negative ion:
the electron cloud reacts.
18. What happened when you dragged the
negative ion around?
19.Why?
20. Based on your observation of the behaviors of the electron cloud, explain why an electron cannot
form an atom with only a neutron.
Part 3 Chemical bonding
21. What happens when two atoms come together?
The formation of a covalent bond
22. Instructions: Click the "Run" button and observe the change of the electron clouds.
23. Draw and describe what the e- clouds look like before and after you hit run
Before
After
24. Drag the "Interatomic distance" slider to make their distance shorter. Be sure to let the model run
for a few seconds between each move.
25. Draw and describe what the e- clouds look like after you hit run at each of these distances:
0.04nm
0.05nm
0.1nm
26. Observe carefully how the electron clouds move. What is the distance at which the electron
clouds start to merge?
27. What is the maximum distance between the two nuclei for a covalent bond to form?_________
28. Draw and explain: Why can’t they get any farther apart and still bond?
29. What is the closest that they can get?______________
30. Draw and explain: Why they can’t get any closer?
Part 4. Chemical Polarity
31. What is chemical polarity and how does it relate to electron cloud?
The polarity of a diatomic molecule
32. Instructions: Click the "Run" button and observe the movement of the electron clouds.
33. Draw and describe what the e- clouds look like before and after you hit run:
Before
After
Draw and Explain what happened
34. Adjust the sliders so that the atoms' electronegativity’s are different and observe what happens.
Repeat this for a number of different settings.
35. Draw and describe what the e- clouds look like after you hit run for each of these
electronegativity’s:
A=4 vs. B=1
A= 3 vs. B=2
A= 2 vs. B=2
Electronegativity Difference =
Electronegativity Difference =
Electronegativity Difference =
Type of Bond
Type of Bond
Type of Bond
36. In the above models, what type of bond is formed when the difference of electronegativity
between the two atoms is greater than 1?
37. How does the electron clouds behavior in questions 34-35 relate to our tug of war activity?
Draw and explain: