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Chemical Bonding and Chemical Interactions
Citation preview
Physical Science
Date: July 19, 2014
Objective: I can predict the oxidation number and number of valence electrons for an element as well as draw Lewis dot diagrams. To Do:• Complete Catalyst (5 minutes) • Have binder ready & periodic table out
Catalyst: Review
Subatomic
Particle
Charge
Location Size
protonelectronneutron
positivenegativeneutral
Inside nucleus
Inside nucleus
outside nucleus
1 amu
1 amu
1/2000
amu
Catalyst: Review② Compare a period to a group on
the periodic table.
• A period is a row on the periodic table• There are 7 periods• A group is a vertical column • There are 8 representative groups
• Both contain elements and provide useful information about atoms
Catalyst: Review
Periods
Groups
Catalyst: Review
③ What can the period or row tell you when drawing Bohr models?
• A period or row tells you how many rings or shells to draw on a Bohr model.
Catalyst: Review
④ Sodium
⑤ Carbon
Remember:• 1st ring: 2
e-• 2nd ring: 8
e-• 3rd ring: 18
e-
Today’s Objective
Objective: I can predict the oxidation number and number of valence electrons for an element as well as draw Lewis dot diagrams.
VocabularyValence electron: An electron on the outermost energy level in an atom 1
valence e-
4 valence
e-
Valence electrons• Atoms in the same family have
the same # of valence electrons
• Elements in the same family have similar properties
Valence electrons1
2 3 4 5 6 78Label your periodic tables as
shown here:
popcorn• We will play popcorn around the
classroom
• We will ask questions about valence electrons
• For example, “How many valence electrons does Nitrogen have?”
• If you answer correctly, you may choose the next student to ask a question to
Vocabulary• Oxidation Number: Refers to the
number of electrons lost or gained during chemical bonding
• When metals and nonmetals form compounds, they lose or gain valence electrons
Vocabulary
• Ionic Bond: A bond between a metal and a nonmetal
• Ion: An atom with a positive or negative charge
Ions• An ion is an atom that has a positive
or negative electric charge • Represented by the plus or minus sign
Na+• Plus sign tells
me that this sodium atom gave an electron away
Oxidation #+1
+2 +3 +-4 -3 -2 -10Label your periodic tables as
shown here:
Oxidation #
• Metals have a positive charge because they lose electrons
• Nonmetals have a negative charge because they gain electrons
Lewis dot diagrams
• Bohr diagrams help us see electron configurations for atoms
• Bohr diagrams help us understand reactivity
• Lewis dot diagrams show valence electrons only
1. Write the chemical symbol 2. Find the # of valence electrons (group #)3. Draw the valence electrons (cross method)
Drawing Electron dot diagrams
Valence electrons = 7
Cl
Examples:
Practice• Using your dry erase board, draw dot
diagrams for the element I call out
• When I say to, hold up your dry erase board
• Work independently
Activity• Complete the Mix & Match Activity
with your table partner
• When finished, raise your hand and I will check your work
• You have 25 minutes to complete correctly
• Pick-up the Periodic Table Challenge when finished
Exit ticket• Complete the Exit Ticket
• You may use your periodic table
• Keep eyes on your own paper
• 10 minutes