Presentation is loading. Please wait.

Presentation is loading. Please wait.

Catalyst 1. Draw the Lewis Structure for BCl3. 2. Draw the Lewis Structure for HCN. 3. Draw the Lewis Structure for PCl5.

Published byWillis Robertson Modified over 5 years ago

Similar presentations

Presentation on theme: "Catalyst 1. Draw the Lewis Structure for BCl3. 2. Draw the Lewis Structure for HCN. 3. Draw the Lewis Structure for PCl5."— Presentation transcript:

1 Catalyst 1. Draw the Lewis Structure for BCl3. 2. Draw the Lewis Structure for HCN. 3. Draw the Lewis Structure for PCl5

2

3 Formal Charges Many compounds have more than 1 possible Lewis structure. Formal charges tells us the “right” Lewis structure. Formal Charge – The charge an element would have if all electrons were shared equally. The “best” structure has: 1. Atoms that have formal charges closest to 0 2. Highest negative charge on the most electronegative atom

4 Calculating Formal Charges
To calculate formal charge:

5 Class Example Draw NCS–, calculate its formal charge and pick the “best” Lewis structure.

6 Table Talk Draw the Lewis structure for PF3 and label the formal charge of all atoms

7 Meet the Bicarbonate Ion…

8 HCO3 – + H+  H2CO3  CO2 + H2O

9 Justify – TPS Which structure of bicarbonate drawn on the board is “right” according to our rules of formal charges?

10

11 Lecture 2.2 – Resonance Structures and Polar Covalent Compounds

12 Today’s Learning Target
LT 2.4 – I can discuss the reason for the formation of resonance Lewis Structures and I can draw resonance structures for a variety of covalent compounds.

13 Resonance Structures Oftentimes, there is more than one “correct” way to draw a Lewis structure. This occurs because there are multiple drawings with the same formal charges.

14 Class Example Draw all the allowed structures for O3

15 Resonance Structures For O3, both structures are equally valid
Resonance Structures – Molecules that require multiple Lewis Structures to describe the distribution of electrons. Both structures are present in equal amounts

16 Resonance Structure for Ozone
Double bared arrow indicates that we can have either structure. The density of electrons can actually be thought of as residing somewhere in the middle of the two structures.

17 Table Talk Draw all the correct structures for SO3-

18 Table Talk Draw all correct resonance structures for HCO2-

19 Coach and Correct

20 Question 1 Draw all resonance structures for the nitrate ion

21 Question 2 Draw all resonance structures for the phosphate ion

22 Question 3 Draw all resonance structures for S2CO-2

23 Question 4 Draw all resonance structures for SCN -

24 Question 5 Draw all resonance structures for CHO2-

25 Amazing Bending Water!

26 Justify – TPS What caused the water to bend?

27 Today’s Learning Targets
LT 2.5 – I can characterize ionic and covalent compounds utilizing the idea of electronegativity. Furthermore, I can discuss how electronegativity differences lead to the formation of polar covalent bonds

28 Electronegativity Electronegativity – The ability of an atom in a molecule to attraction electrons to itself. Increases as you move across a period Adding more protons, but not adding more energy levels Decreases as you go down a group Adding more energy levels makes it harder for the nucleus to attract new electrons

29

30 Covalent Bond Polarity
Oftentimes, when atoms are in a covalent bond, electrons are not shared equally. Nonpolar Covalent Bond – Electrons shared equally between the atoms Polar Covalent Bond – Electrons shared unequally due to difference in electronegativity Electrons in a covalent bond reside closest to the atom that is most electronegative

31 H F Because fluorine is drastically more electronegative, it holds electrons closer to itself when in a covalent bond with hydrogen.

32 H F Hydrogen is given a partial positive charge and fluorine is given a partial negative charge

33 Table Talk Label the location of the partial positive and partial negative charges in water.

34 Dipole Moments The creation of a polar compound leads to the concentration of charge at the poles of the element. Indicate dipole moment with an arrow that starts at positive and goes to the negative end H F H F

35 Bonding is a Spectrum The difference in electronegativity tells us the type of bond that a compound has. Don’t worry about exact values, you can do this qualitatively Electronegativity difference of 0 = non-polar covalent Electronegativity difference of 0.1 to 2 = polar covalent Electronegativity difference of 2 and greater = ionic bond

36 Around the World Determine if the compounds around the room are ionic, polar covalent, or non-polar covalent

37 Exit Ticket 1. Draw all the resonance structures for NO3–. Label the formal charges on all atoms. 2. Draw the Lewis structure for HCl. Draw the dipole moment on the compound

38 Rate Yourself Based on the exit ticket and your current level of understanding, rate yourself 1 – 4 on LT 2.1, 2.2, 2.3, 2.4, and 2.5

39

40 Closing Time You should read section 8.1 – 8.7 for Thursday/Friday
Answer questions 8.1, 8.4, 8.22, 8.24, 8.39, 8.41, 8.47, 8.48, 8.52, 8.63, and 8.64 for Thursday/Friday

Download ppt "Catalyst 1. Draw the Lewis Structure for BCl3. 2. Draw the Lewis Structure for HCN. 3. Draw the Lewis Structure for PCl5."

Similar presentations

Chapter 9 Notes – Part II Mr Nelson 2009.

Chapter 9 Notes – Part II Mr Nelson 2009.
Problem Set: Polar, Nonpolar, and Ionic Bonds

Problem Set: Polar, Nonpolar, and Ionic Bonds
Polar Covalent Bonds. Polar bond - A type of covalent bond between two atoms in which electrons are shared unequally, resulting in a bond in which one.

Polar Covalent Bonds. Polar bond - A type of covalent bond between two atoms in which electrons are shared unequally, resulting in a bond in which one.
Chapter 10 Properties of Solids and Liquids

Chapter 10 Properties of Solids and Liquids
Resonance Structures. The more correct way to do Lewis Dot Structures (book method) 1. Get the sum of all valence electrons from all atoms. Ignore which.

Resonance Structures. The more correct way to do Lewis Dot Structures (book method) 1. Get the sum of all valence electrons from all atoms. Ignore which.
Molecular compounds. SO FAR...  We’ve seen how ions combine to form ionic compounds  Electrons are gained or lost so that the atom can form an ion 

Molecular compounds. SO FAR...  We’ve seen how ions combine to form ionic compounds  Electrons are gained or lost so that the atom can form an ion 
Homonuclear & Heteronuclear bonds Homonuclear bondsHetronuclear bonds Ethane (C 2 H 6 ) Hydrazine (N 2 H 4 ) Hydrogen peroxide (H 2 O 2 )

Homonuclear & Heteronuclear bonds Homonuclear bondsHetronuclear bonds Ethane (C 2 H 6 ) Hydrazine (N 2 H 4 ) Hydrogen peroxide (H 2 O 2 )
Section 5.4—Polarity of Molecules

Section 5.4—Polarity of Molecules
Covalent Bonding Topics covered Homework Covalent bonding

Covalent Bonding Topics covered Homework Covalent bonding
Chapter 11 Chemical Bonding.

Chapter 11 Chemical Bonding.
Resonance Structures. Book way to do Lewis Dot Structures 1. Get the sum of all valence electrons from all atoms. Ignore which electron came from which.

Resonance Structures. Book way to do Lewis Dot Structures 1. Get the sum of all valence electrons from all atoms. Ignore which electron came from which.
Chapter 8 sections 1-7 Chapter 9 sections 1-6 Ionic – Formed by the electrical attraction of a positive cation to a negative anion. Don’t worry about.

Chapter 8 sections 1-7 Chapter 9 sections 1-6 Ionic – Formed by the electrical attraction of a positive cation to a negative anion. Don’t worry about.
Section 12.1 Characteristics of Chemical Bonds 1.To learn about ionic and covalent bonds and explain how they are formed 2.To learn about the polar covalent.

Section 12.1 Characteristics of Chemical Bonds 1.To learn about ionic and covalent bonds and explain how they are formed 2.To learn about the polar covalent.
8-2: Polarity. Remember electronegativity… An atom’s ability to attract electrons in a chemical bond. Polar bond: electrons are shared unequally between.

8-2: Polarity. Remember electronegativity… An atom’s ability to attract electrons in a chemical bond. Polar bond: electrons are shared unequally between.
Chemical Bonding. Although we have talked about atoms and molecules individually, the world around us is almost entirely made of compounds and mixtures.

Chemical Bonding. Although we have talked about atoms and molecules individually, the world around us is almost entirely made of compounds and mixtures.
Single Covalent Bonds For molecular compounds, we use Lewis structures to depict neighboring atoms as sharing some or all of their valence electrons in.

Single Covalent Bonds For molecular compounds, we use Lewis structures to depict neighboring atoms as sharing some or all of their valence electrons in.
Chemical Bonding List the three types of bonds List the substances that compose the three types of bonds Draw the Lewis Dot Structure, Molecular Geometry,

Chemical Bonding List the three types of bonds List the substances that compose the three types of bonds Draw the Lewis Dot Structure, Molecular Geometry,
General, Organic, and Biological Chemistry Fourth Edition Karen Timberlake 5.7 Electronegativity and Bond Polarity Chapter 5 Compounds and Their Bonds.

General, Organic, and Biological Chemistry Fourth Edition Karen Timberlake 5.7 Electronegativity and Bond Polarity Chapter 5 Compounds and Their Bonds.
How are molecules depicted? Ch. 9, sections 3 & 4.

How are molecules depicted? Ch. 9, sections 3 & 4.
CHAPTER 8 Basic Concepts in Chemical Bonding. Introduction Attractive forces that hold atoms together in compounds are called chemical bonds. The electrons.

CHAPTER 8 Basic Concepts in Chemical Bonding. Introduction Attractive forces that hold atoms together in compounds are called chemical bonds. The electrons.

Similar presentations

Ads by Google