ACTIVITY VII-CHEMISTRY-2012-13
ELECTRON ARRANGEMENT DETERMINES THE CHEMICAL BEHAVIOR OF
ATOMS
IONIC BONDS ARE ATTRACTIONS BETWEEN IONS OF OPPOSITE
CHARGE
ANTICIPATORY SET:
1.
2.
3.
4.
5.
Create two circles with 8 chairs each
Ask 7 students to sit in first circle
Ask 9 students to sit in second circle
Have students describe the situation
How can we solve this problem?
INTRODUCTION:
Atoms seek to become stable by filling their outer electron shell. Atoms
that have a full outer electron shell are stable and unreactive, which means
they do not participate in chemical reactions & thus do not bond with other
atoms. If an atom has only one electron shell it needs two electrons to be
filled, stable, & unreactive. If an atom has two electron shells, the second
shell needs eight electrons to be filled, stable, & unreactive. If an atom has
three electron shells, the third electron shell needs eight electrons to be
filled, stable, & unreactive even though it can hold up to 18 electrons.
A. MATERIALS:
1. Three different colors of M&M’s
2. Cup, bowl, or Ziplocs bag
3. Periodic table
4. Atomic model handout
B. PROCEDURE- 20 minutes
1. Use the paper atomic models and M&M’s to build a fluorine atom and a
sodium atom.
2. Answer questions below:
a. How many electrons are in the sodium atom?
b. How many electron shells will the sodium atom have?
c. How many electrons are in the first electron shell of the
sodium atom?
d. How many electrons are in the second electron shell of the
sodium atom?
e. How many electrons are in the third electron shell of the
sodium atom?
f. Does the sodium atom have a full outer electron shell? If not
how many electrons does it need to fill its outer energy level?
g. Is the sodium atom currently neutral? Explain
h. How many electrons are in the fluorine atom?
i. How many electron shells will the fluorine atom have?
j. How many electrons are in the first electron shell of the
fluorine atom?
k. How many electrons are in the second electron shell of the
fluorine atom?
l. How many electrons are in the third electron shell of the
fluorine atom?
m. Does the Fluorine atom have a full outer electron shell? If not
how many electrons does it need to fill its outer energy level?
n. Is the Fluorine atom currently neutral? Explain
o. Would you consider the sodium atom and fluorine atom stable
or unstable? Why?
p. Would you consider the sodium atom and fluorine atom
unreactive or reactive? Why?
q. What can they do to become stable and unreactive?
3. STOP AND WAIT FOR CLASS DISCUSSION
4. Move an electron from sodium to fluorine to form two stable atoms
(ions).
a. How many protons and electrons does sodium now have?
b. Will the sodium be neutral, positively charged, or
negatively charged? Explain.
c. Is the sodium ion more or less stable now?
d. How many protons and electrons does Fluorine now have?
e. Will the Fluorine be neutral, positively charged, or
negatively charged? Explain.
f. Is the Fluorine ion more or less stable now?
g. Which atom gained an electron and which atom gave up an
electron?
h. What is the attractive force that holds an ionic bond
together?
5. STOP AND WAIT FOR CLASS DISCUSSION
6. Students should build LiCl, MgO and NaCl and draw before and after
diagrams of each.
7. ANSWER QUESTIONS BELOW:
a. In each of the molecules you’ve modeled, which atom has become the cation
(positively charged ion), and which is the anion (the negatively charged ion)?
b. Which elements of the periodic table tend to become negative ions (have the
greatest potential for acquiring electrons)? Why?
c. Which elements of the periodic table tend to be positive ions (have the
weakest ability to retain their electrons)? Why?
d .Which columns would combine well in order for both to be more stable?
e. Which elements on the periodic table tend to make ionic bonds?
f. How does electronegativity correlate with ionic bonding?
8.STOP AND WAIT FOR CLASS DISCUSSION
9. Check for understanding
a. How do atoms behave?
b. Which subatomic particle determines how an atom behaves when
it encounters another atom?
c. How many electrons can the first energy level hold?
d. How many electrons can the second energy level hold?
e. How many electrons can the third energy level hold if it is the
outermost energy level?
f. Which energy level determines behavior of an atom?
g. What can you say about an atom with a full outer energy level?
h. What can you say about an atom with an unfilled outer energy
level?
I. What is one way an unstable atom will become stable?
j. What is the attraction force in ionic bonds?
10. WHOLE CLASS DISCUSSION