1. Chemistry Do Now
Directions: Use yesterday’s notes to answer each question on covalent bonds. 1) Explain the duet rule. 2) Explain the octet rule. 3) Define valence. 4) Why do elements want to form bonds? 5) What are the 3 types of covalent bonds?

2. Chemistry Do Now KEY
1) Explain the duet rule. The duet rule states that the 1st five elements will bond with other elements to have 2 valence electrons in order to have an electron configuration like helium. 2) Explain the octet rule. The octet rule states that most elements will bond with other elements to have 8 valence electrons in order to have an electron configuration like their nearest noble gas. 3) Define valence. Valence means the outer electron shell. 4) Why do elements want to form bonds? To become stable 5) What are the 3 types of covalent bonds? Single, double and triple covalent bond

3. Reminders Homecoming/Spirit Week – Today is Twin Day.
Pep Rally
Football Game
Dance
Parent-teacher conferences and PD for staff (schools closed for students) on Monday, November 6, 2017
1st Quarter ends on Thursday, November 9, 2017 (12 school days)

4. Objective #1
Students will know how intermolecular forces (IMFs) between atoms that share pairs of electrons (covalent bonding) determine the properties of the molecule by performing a close read on forming polymers, answer text-dependent questions based on the article, take notes on covalent bonding and answering concept questions. Mastery Level: 25 pts. on close read annotations, 4/6 (67%) on TDQs, and ¾ on exit ticket questions

5. Objective #2
Students will know how to draw the Lewis dot diagrams for covalent compounds through the sharing of one, two or three pair(s) of valence electrons by applying the rules to draw Lewis dot diagrams of covalent compounds and answering an exit ticket question. (Mastery Level: 70% [14/20]or better)

6. Homework – Complete TONIGHT
Draw the Lewis Dot Diagram for each molecule.
PF3 O2 N2
CO2 CO
CF2Cl2

7. Engage
Show the students the YouTube video “Covalent Bonding” Source: c Show the students the YouTube video “How to draw Lewis Structures: Five Easy Steps” Source:

8. Explore
Students will perform a close read on the Slime article. As the students read the text, they will annotate using the symbols posted on charts in the classroom. Following their annotations, the students will answer 6 scaffolded text- dependent questions. 1) What is the main idea of the article? 2) Cite 3 statements from the article to support your main idea. 3) The author uses two illustrations in the article. How does the author use the pictures to help the reader understand polymerization? 4) What is the author’s purpose for writing this article: entertainment, information or persuasion? How do you know? 5) How is the text organized to help build your understanding of the main idea? 6) Now that you have read the article, explain what the author failed to discuss? Explain why this topic should have been discussed in the article. Where should this topic have been mentioned in the article? Why?

9. Vocabulary Words Covalent bond Electron sharing Single covalent bond
Double covalent bond
Triple covalent bond
Polar covalent bond
Non-polar covalent bond
Lewis Dot Diagram

10. Explain intermolecular forces (covalent bonding)
Students will take notes.
Explain intermolecular forces (covalent bonding)

11. Covalent Bonding
Unit III: Combining Atoms
October 24, 2017

12. Review of Ionic Bonding
We learned about electrons being transferred (“given up” or “stolen away”).
This type of “tug of war” between a METAL and NONMETAL is called an IONIC BOND, which results in a SALT being formed

13. Molecular Compounds
Now, you will learn about another type of bond in which electrons are shared
Covalent Bonds are atoms held together by SHARING electrons between NONMETALS

14. Salt versus Molecules
A metal cation and nonmetal anion are joined together by an ionic bond called SALT
A group of atoms joined together by a covalent bond is called a MOLECULE
A Compound is a group of two or more elements bonded together (Ionic or Covalent).

15. Ionic vs Covalent

16. Monatomic vs. Diatomic Molecules
Most molecules can be monatomic or diatomic
Diatomic Molecule is a molecule consisting of two atoms
There are 7 diatomic molecules (SUPER 7) – N2, O2, F2, Cl2, Br2, I2, H2
You can also remember them as: H2O2F2Br2I2N2Cl2

17. Properties of Molecular Compounds
Liquids or gases at room temperature
Lower Melting Points than Ionic Compounds (which means that they are weaker than ionic)

18. Molecular Formulas
The Molecular Formula is the formula of a molecular compound
It shows how many atoms of each element a molecule contains
Example
H2O contains 3 atoms (2 atoms of H, 1 atom of O)
C2H6 contains 8 atoms (2 atoms of C, 6 atoms of H)

19. Practice
How many atoms total and of each do the following molecular compounds contain? H2 CO
CO2
NH3
C2H6O

20. Practice: True or False
All molecular compounds are composed of atoms of two or more elements.
All compounds are molecules.
Molecular compounds are composed of two or more nonmetals.
Atoms in molecular compounds exchange electrons.
Molecular compounds have higher melting and boiling points than ionic compounds.

22. Ionic versus Covalent IONIC COVALENT Bonded Name Salt Molecule
Bonding Type
Transfer e-
Share e-
Types of Elements
Metal & Nonmetal
Nonmetals
Physical State
Solid
Solid, Liquid, or Gas
Melting Point
High (above 300ºC)
Low (below 300 ºC)
Solubility
Dissolves in Water
Varies
Conductivity
Good
Poor

23. Covalent Bonding
Remember that ionic compounds transfer electrons in order to attain a noble gas electron configuration
Covalent compounds form by sharing electrons to attain a noble gas electron configuration
Regardless of the type of bond, the Octet Rule still must be obeyed (8 valence electrons)

24. Single Covalent Bond
A Single Covalent Bond consists of two atoms held together by sharing 1 pair of electrons (2 e-)

25. Single Covalent Bond
A Single Covalent Bond consists of two atoms held together by sharing 1 pair of electrons (2 e-)

26. Double Covalent Bonds
Sometimes atoms attain noble gas configuration by sharing 2 or 3 pairs of electrons
A Double Covalent Bond is a bond that involves 2 shared pairs of electrons (4 e-)

27. Triple Covalent Bond
A Triple Covalent Bond is a bond that involves 3 shared pairs of electrons (6 e-)

28. Covalent Bonds

29. Extend
1) Explain how a single covalent bond is formed, double covalent bond, and a triple covalent bond. 2) Draw a Venn diagram comparing and contrasting a nonpolar and polar covalent bond.

30. Evaluate
Exit Ticket Questions on IMF 1) What are the differences between an ionic and a covalent bond? 2) What is meant by unequal sharing of electrons? How does this result in the formation of a polar molecule? 3) What is meant by equal sharing of electrons? How does this result in the formation of a nonpolar molecule? 4) Which type of bond, ionic or covalent, has the higher intermolecular force? How do you know?
SKILL MASTERY LEVELS (Based on 100 maximum points): 4/4 correct (100 points): SKILL EXCEPTIONALLY MASTERED 3/4 correct (75 points): SKILL ADEQUATELY MASTERED <3/4 correct (<75 points): SKILL NOT MASTERED

31. Lewis Structures of Covalent Compounds
Edited By
Mr. Richards
October 23, 2017
Source:

32. The 2 major rules for why atoms bond
#1: Duet Rule
2 hydrogen atoms forming a single covalent bond
The rule of duet refers to the first five elements of the periodic table. They are most stable when the electron shell is filled with two (duet) electrons. Hydrogen wants to gain one electron, Lithium, Beryllium and Boron want to lose 1,2, or 3 electrons respectively in order to have a filled outer shell like Helium, their nearest noble gas.

33. The 2 major rules for why atoms bond
#2: Octet Rule
2 fluorine atoms formed a single covalent bond (F2)
A stable arrangement is attended when the atom is surrounded by eight electrons. This octet can be made up by own electrons and some electrons which are shared. Thus, an atom continues to form bonds until an octet of electrons is made.

34. What’s so special about the Noble Gases?
The noble gases rarely form compounds. They are the most stable elements (full octet, no charge), so they have no reason to react. All other elements attempt to gain, lose, or share electrons to achieve a noble gas arrangement.

35. Exceptions to the Octet Rules
Here are 4 elements that do not follow the octet rule. You need to know them so that you will have an easier time drawing Lewis Dot Diagrams.
Beryllium only needs 4 electrons in its valence shell to be stable.
Boron only needs 6 electrons in its valence shell to be stable.
Phosphorus can have 8 or 10 electrons in its valence shell to be stable.
Sulfur can have 8 or 12 electrons in its valence shell to be stable.

36. Lewis Symbols
Represent the number of valence electrons as dots
Valence number is the same as the Periodic Table Group Number
Groups

37. Each Covalent Bond contains two electrons
What is covalent bonding?
Covalent Bonding results from the sharing of two electrons between two atoms (usually non-metals) resulting in molecules
Octet Rule applies
Triple bond
Each Covalent Bond contains two electrons

38. Covalent Bonding – Atoms Share Electrons

39. Covalent bonding and Lewis structures
(1) Covalent bonds are formed from sharing 1 pair, 2 pairs or 3 pairs of electrons by two atoms.
Molecules possess only covalent bonds.
The bedrock rule for writing Lewis structures for the first full row of the periodic table is the octet rule for C, N, O and F: C, N, O and F atoms are always surrounded by eight valence electrons.
(4) For elements hydrogen through boron, the duet rule is applied: H atoms are surrounded by two valence electrons.

40. Let’s Stop to draw Lewis Dot Diagrams for:
Covalent Compounds

41. Before we can draw Lewis Dot Diagrams of Covalent Compounds, we have to learn about electronegativity
Electronegativity is defined as an atom’s affinity or attraction to valence electrons. Metals have a LOW affinity for valence electrons and, therefore, cannot keep their valence electrons. Nonmetals have a HIGH affinity for valence electrons and, therefore, take electrons from the valence shell of metals. As you move from left to right on the Periodic Table of Elements, the electronegativity value INCREASES.

42. How do you read an Electronegativity PTE?
Fluorine has the HIGHEST electronegativity value – 4.0
Francium has the LOWEST electronegativity value – 0.7

43. How does the electronegativity value play a role in drawing Lewis dot diagrams?
The electronegativity value can help you determine the central atom of a covalent Lewis dot diagram. For example, suppose you had to draw the Lewis dot diagram for hydrogen nitrate (HNO3). Hydrogen can never, ever, ever, ever, ever be the central atom so that leaves you with nitrogen or oxygen. Which element is your central atom? Take out your Electronegativity PTE and look up their EN values. N has an EN value of 3.0 and oxygen has an EN value of 3.5. The element with the LOWER electronegativity is the central atom. Nitrogen is your central atom.

44. Rules for drawing Lewis dot diagrams for covalent (molecular) compounds
COUNT the total number of valence electrons you have to work with. YOU MAY NOT ADD ADDITIONAL ELECTRONS TO ATTAIN THE OCTET RULE. THAT’S CHEATING! Think of how the atoms will SHARE their valence electrons such that the Octet or Duet rules are attained. You may bond 1 pair, 2 pairs or 3 pairs of electrons ONLY! Using a pencil is highly recommended because there are times you have to rethink your electron arrangement.
DETERMINE which atom will be your central atom. Normally, it’s the first element written in the chemical formula. HOWEVER, hydrogen can NEVER be the central atom even if it’s the first element in the chemical formula. Another way to determine the central atom is by looking up the electronegativity value of the atoms. The one with the LOWEST electronegativity value is the central atom. Once you have determined the central atom, DRAW the central atom’s Lewis Dot Diagram. DRAW the Lewis dot diagrams of the other atoms.

45. Guided Practice
F2 SiH4 Cl2 NH3 SCl2 H2O

46. Independent Practice
H2 H2S O2 OCl2 N2 C2H2 NH3