Catalyst
• What are bonds between non-metals? Metals
and non-metals? Only metals?
• What is the ionic compound formed between
NH4+ and NO32-?
End
Quiz
•You have 20 minutes to complete the quiz
•This should be done without notes and should
be completed silently. Consequences will be
enforced.
Mercury Fulminate [Hg(CNO)2]
Ammonium Nitrate [NH4NO3]
Justify-Think-Pair-Share
• WRITE: Which do you think is more explosive,
ammonium nitrate or mercury fulminate?
Which would kill you faster? Why?
• In your notebooks: SHARE and JUSTIFY
Organic
Chemistry
+
Organic Chemist
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LECTURE 2.5 – LEWIS DOT
STRUCTURES
Learning Target
LT 2.7 – For a given covalent compound, I can
draw a Lewis Dot diagram for the compound
and explain how it illustrates the covalent bond.
Review: Lewis Structures for
Elements
Example: Chlorine
1: Group 7A
1. Find group number
2. Group # = # valence
electrons
3. Draw valence
electrons as dots
4. Each side must have
one electron before
pairing
2: 7 valence electrons
3/4:
1
2
3
7
4
6
5
Lewis Structures for Ionic Bonds
Na
Cl
Ammonium Nitrate [NH4NO3]
How do you show electrons being
shared?
Mercury Fulminate [Hg(CNO)2]
Rules for Lewis Dot Structures
1. Decide how many valence electrons are
possessed by each atom.
2. The central atom is always carbon (if it is
present) and/or the element that has the
lowest electronegativity.
3. Arrange electrons appropriately so that each
atom contributes one electron per bond.
4. Count electrons to make sure Octet Rule is
obeyed.
F>O>N>Cl
FONECALL
Class Example
•Draw the Lewis structure for H2S
Key Points
• Each bond has 2 electrons
• Hydrogen and halogens are NEVER central
atoms and may only form one bond.
• Hydrogen is never bonded to another
hydrogen (except for H2)
Table Talk
•Draw the Lewis structure for NH3 (Hint: all 3
hydrogens are bonded to the nitrogen)
Stop and Jot
•Draw the Lewis structure for C2H6
Covalent Lewis Structures
• Please read through
both parts of the
sheet entitled “Lewis
Dot Structure
Tutorial”
Multiple Bonds
• Single bond = 2 electrons
• Double bond = 4 electrons
• Triple bond = 6 electrons
Rules for Multiple Bonds
5. If Octets are incomplete, move one electron
from each neighboring atom to make a double
bond.
6. Repeat step 5 until Octets are full.
7. Redraw electrons on remaining atoms so
that they are in pairs.
Class Example
•Draw the Lewis Structure for CO2
Table Talk
•With your table, draw the Lewis structure of
C2H4
Stop and Jot
•Draw the Lewis structure for CO
Honors: Challenge Problems
1.
2.
3.
4.
CH2O
HCN
SOCl2
C6H6 (very difficult!)
SUMMARIZE
Rate Yourself!
Using your exit ticket score, rate yourself 1 – 4
on LT 2.7
Closing Time
•Homework 2.7 – Lewis Structure Practice
•UNIT 2 TEST NEXT WEDNESDAY (BRIGHT AND
EARLY, 1st PERIOD!)