As you come in,

Materials:– Grab a packet, paper and pencil

Plan:– Return lab practical and cumulative quiz– Learn about ionic bonding

Homework:– 7-1 & 7-3 Practice Problems

Assessment:– Polyatomic Ion Quiz - FRIDAY

Unit Four: Bonding/Nomenclature

GPS SC1: Students will analyze the nature of matter and its classifications.

Classification of Matter

Mixtures

Elements

MetalCation

NonmetalAnion

Ionic

Nonmetal Nonmetal

Covalent

Compounds

Pure Substances

Matter

Ionic Bond

Ionic bond: the electrostatic force that holds oppositely charged particles together in an ionic compound

Compounds that contain ionic bonds are called ionic compounds.

Ionic compounds form between metals and nonmetals.

Criss-Cross Method for Writing Chemical FormulasLet’s predict the formula for the stable ionic compound that contains:

–calcium ion and phosphide

–aluminum ion and sulfate

–tin(II) and carbonate

Valence Electrons & Stability Review

Let’s talk about the formulas that you just completed.– Questions to ALWAYS ask yourself after

criss-crossing:• How many of the cations are in the compound?• How many of the anions are in the compound?• Is the ratio (AKA formula unit) reduced?• Are transition metals involved?

What is the chemical formula for sodium hypochlorite?

A.) NaCl

B.) NaClO

C.) NaClO2

D.) NaClO3

E.) Na(ClO)

What is the chemical formula for sodium acetate?

A.) Na2C2H3O

B.) (Na)(C2H3O2)

C.) NaC2H3O2

D.) Na3C2H3O2

E.) NaCHO

What is the chemical formula for tin(IV) oxide?

A.) Sn4O

B.) Sn4O2

C.) Sn2O

D.) Sn2O4

E.) SnO2

What is the chemical formula for magnesium oxide?

A.) MnO

B.) MnO2

C.) MgO

D.) Mg2O2

E.) MgO2

What is the chemical formula for nickel(II) nitrate?

A.) Ni2NO3

B.) Ni1NO32

C.) NiNO3

D.) (Ni)(NO3)2

E.) Ni(NO3)2

What is the chemical formula for magnesium phosphate?

A.) MgP

B.) Mg3P2

C.) MgPO4

D.) Mg2(PO4)3

E.) Mg3(PO4)2

Writing Ionic Compound Names from the Formulas

When given a formula, analyze the ions.

Identify the two ORIGINAL ions that were criss-crossed to give the formula.

“Backwards criss-crossing” or “un-criss-crossing” will NOT work in many cases!

You’ll have to work harder than that!

Practice Writing Names from Chemical Formulas

Write the name of the compound that is represented by the following formulas:– MgCl2– Na2SO4

– PbS

– Cu2SO3

A few more…

FeSO4

NiNO3

CrClO3

FeO

Sn2S

Name the following compound: PbS

A.) lead sulfur

B.) lead sulfide

C.) lead (I) sulfide

D.) lead (II) sulfide

E.) lead sulfate

Name the following compound: Cu2CO3

A.) copper carbonate

B.) copper (I) carbonate

C.) copper (II) carbonate

D.) copper (II) carbonate (III)

E.) copper carbontrioxide

Name the following compound: CrPO4

A.) chromium phosphate

B.) chromium (I) phosphate

C.) chromium (II) phosphate

D.) chromium (III) phoshate

E.) chromium (IV) phosphate

Name the following compound: NiSO4

A.) nickel sulfate

B.) nickel (I) sulfate

C.) nickel (II) sulfate

D.) nickel (III) sulfate

E.) nickel (IV) sulfate

Name the following compound: Al2(SO4)3

A.) aluminum (III) sulfate

B.) aluminum sulfate

C.) aluminum (II) sulfate

D.) aluminum sulfite

E.) aluminum sulfide

Name the following compound: KBr

A.) potassium bromide

B.) potassium (I) bromide

C.) potassium bromite

D.) potassium bromate

Name the following compound: TiO2

A.) titanium oxide

B.) titanium (II) oxide

C.) titanium (IV) oxide

D.) titanium oxide (II)

Name the following compound: Cr2SO3

A.) chromium (II) sulfate

B.) chromium (II) sulfite

C.) chromium (I) sulfite

D.) chromium sulfate

Write the chemical formula for zinc selenide.

A.) ZnSe

B.) Zn2Se

C.) ZnSe2

D.) Zn2Se2

Write the chemical formula for calcium nitrate.

A.) CaNO3

B.) CaNO2

C.) Ca(NO3)2

D.) Ca(NO2)2

E.) Ca3N2

Write the chemical formula for cobalt(III) phosphide.

A.) Co3P

B.) Co3P3

C.) CoP

D.) CoPO3

E.) CoPO4

Formula unit ratios form beautiful crystals…Ionic compounds are crystals!

What You’ll See in Our Lab

Ionic compound solids that form when two solutions are mixed

“Snow Globe” effectSeparation

line Paint effect

Forming Ionic Compounds Pre-Lab

Lab Purpose: To write formulas and names of 20 ionic compounds; to see ionic compounds formed in the lab

Lab Safety: Wear goggles and apron. Avoid contact with chemicals. Wash your hands after the lab. Do not mix up the pipettes.

Lab Procedure: Note the layout of the test tubes. Place 4-5 drops of each chemical into the well-plate.

Lab Report: Turn in your data table on Monday.

Post-Lab Clean-up: Place your well-plate on the table beneath the goggle cabinet. Wipe down your station.

Physical Properties of Ionic Compounds

Applying heat to melt sodium chloride

Applying a current to test conductivity of

sodium chloride

Covalent Bonding

Why do atoms bond?

Remember that ionic compounds form by gaining and losing electrons.Covalent compounds form when 2 atoms both need electrons. They can both achieve the full octet by sharing electrons.

What is a covalent bond?

Covalent bond: chemical bond that results from sharing electronsCovalent bonding generally occurs when elements are relatively close together on the periodic table.The majority of covalent bonds form between nonmetallic elements…often groups 4A to 7A.

Naming Covalent Compounds

First, you must be sure that the compound is COVALENT by analyzing the formula.

Second, you use prefixes to communicate the number of atoms of each element that form the compound.

Example: H2O = dihydrogen monoxide

Prefixes

One = mono

Two = di

Three = tri

Four = tetra

Five = penta

Six = hexa

Seven = hepta

Eight = octa

Nine = nona

Ten = decaNEVER USE MONO ON THE FIRST ELEMENT NAME.

ALWAYS USE THE -IDE ENDING ON THE SECOND ELEMENT NAME.

Name the following compound: P4S5

A.) phosphorus sulfide

B.) tetraphosphorus pentasulfur

C.) tetraphosphorus pentasulfide

D.) tetraphosphide pentasulfide

E.) phosphorus (IV) sulfide

Name the following compound: SeF6

A.) selenide fluoride

B.) selenium fluorine

C.) monoselenium hexafluoride

D.) selenium hexafluoride

E.) monoselenide hexafluoride

What is the chemical formula for dinitrogen trioxide?

A.) NO

B.) N2O

C.) N2O2

D.) N2O3

E.) N3O2

As you come in,

Materials:– Keep your phone. If you don’t have a smart phone, grab a

laptop and login.

Plan:– Socrative app and Edmodo app– Take Ionic Compound Quiz– Get test results back– Learn how to name acids (Take Socrative quiz)– Learn how to draw Lewis structures

Assessments:– Covalent & Acids Naming/Formula-writing Quiz - Tomorrow

Add AppIt’s FREE. Don’t worry!

Search app store for “Socrative Student”

Install app

If you don’t have a smart phone, don’t worry! You’ll use a laptop in class later to do the same activities.

Add AppIt’s FREE, too.

Enable you to do practice quizzes or watch preview videos on your phone.

Search app store for “Edmodo”

Install app

Again, you can do the same thing on a computer. Don’t worry if you don’t have a smart phone!

DEVICE DOWNCell phone goes FACE DOWN on the top corner of your desk.

It stays there until Mrs. Tarvin gives the DEVICE UP signal.

Any deviation from the rule: phone to the pocket at front of room & use a laptop instead

DEVICE DOWNIonic Compound QuizIonic Compound Quiz– Need: Pencil/pen & periodic table

After the quiz, look over your Periodic Table test results. We’ll go over the test on Friday since your cumulative quiz is Monday.

If you have time, practice naming and writing formulas for covalent compounds in your practice packet.

Naming AcidsAcids are compounds that contain hydrogen ion bonded to an anion, except water.

Two types of acids:– Binary Acids - “Hydro____ic acid”

• Examples: HCl, HBr, H2S,

– Oxyacids - “_____ic acid” OR “____ous acid”

• Examples: H2SO4, HNO3, HC2H3O2

• ic = ate anion; ous = ite anion

DEVICE UPOpen the Socrative App.– On a laptop: m.socrative.com

Enter the room #: 189001

Wait for me to start the activity.

You’ll practice naming acids with 5 multiple choice questions.

Lewis Structures

Lewis Structures

Lewis structures: electron-dot diagrams show how electrons are arranged in molecules (AKA covalent compounds)– Diagrams show ONLY valence electrons.– Dashes represent “bonding pairs”– Dots represent “lone pairs” or “nonbonding pairs”.– Brackets and charge signify polyatomic ions.

How to Draw Lewis Structures

1. Find the total # of valence electrons in the molecule.2. Divide this number by 2. This is the number of bonding

pairs.3. Arrange the elements to show a central atom and terminal

atoms. The central atom is usually first in the formula, and hydrogen is always terminal.

4. Place one bonding pairs between the central atom and each terminal atom.

5. Place the remaining pairs around the terminal atoms…if they need more electrons. Put the rest around the central atom.

6. Check to be sure that multiple bonds don’t exist.

Analyze the StructureLewis structures are drawn to predict the type of covalent bond.– Polar covalent: One atom has a significantly

higher electronegativity than the other atom. The bonding electrons are shared UNEVENLY as a result.

– Nonpolar covalent: The atoms have similar electronegativity values, so the bonding electrons are shared EVENLY.

Determine PolarityDraw the Lewis Structure.Look at the central atom.– Does it have a surrounding atom

that differs from the others?– Does it have a lone pair of

electrons?If yes to either, then the molecule is polar.

Polar molecules WILL dissolve in water which is significant in MANY situations.

Example #1: CH4– Name the compound

• Carbon tetrahydride– Total valence electrons

• 4 + 1 + 1 + 1 + 1 = 8– Bonding pairs

• 8/2 = 4 bonding pairs– Arrange the atoms

• Remember the H is always terminal.– Place bonding pairs between the C & each H– How many pairs remain?

• O remaining pairs– Check for multiple bonds. (Does each atom have 8 valence

electrons?)• Yes, so there are no multiple bonds needed.

Example #2: NH3– Name the compound

• Nitrogen trihydride (AKA ammonia)– Total valence electrons

• 5 + 1 + 1 + 1 = 8– Bonding pairs

• 8/2 = 4 bonding pairs– Arrange the atoms

• Remember the H is always terminal.– Place bonding pairs between the N & each H– How many pairs remain?

• 4 pairs - 3 pairs used = 1 remaining pair• Add the remaining pair to the terminal first...then the central.

– Check for multiple bonds. (Does each atom have 8 valence electrons?)

• Yes, so there are no multiple bonds needed.

When the central atom has a lone pair

of electrons, the molecule bends.

Lone pairs of electrons take up

lots of space.

Example #3: Br2– Name the compound

• Bromine– Total valence electrons

• 7 + 7 = 14– Bonding pairs

• 14/2 = 7 bonding pairs– Arrange the atoms

• Two atoms are arranged next to each other.– Place bonding pairs between the two Br atoms– How many pairs remain?

• 7 pairs - 1 pairs used = 6 remaining pairs• Add the remaining pair to the terminal first...then the central.

– Check for multiple bonds. (Does each atom have 8 valence electrons?)

• Yes, so there are no multiple bonds needed.

Example #4: O2– Name the compound

• Oxygen gas– Total valence electrons

• 6 + 6 = 12– Bonding pairs

• 12/2 = 6 bonding pairs– Arrange the atoms

• Two atoms are arranged next to each other.– Place bonding pairs between the two O atoms– How many pairs remain?

• 6 pairs - 1 pair used = 5 remaining pairs• Add the remaining pair to the terminal first...then the central.

– Check for multiple bonds. (Does each atom have 8 valence electrons?)

• No, so there ARE multiple bonds needed.

Example #5: CO2– Name the compound

• Carbon dioxide– Total valence electrons

• 4 + 6 + 6 = 16– Bonding pairs

• 16/2 = 8 bonding pairs– Arrange the atoms

• C should be central with an O on each side. (symmetrical)– Place bonding pairs between the C and each O atom– How many pairs remain?

• 8 pairs - 2 pairs used = 6 remaining pairs• Add the remaining pairs to the terminal first...then the central.

– Check for multiple bonds. (Does each atom have 8 valence electrons?)

• No, so there ARE multiple bonds needed.

Example #6: CO– Name the compound

• Carbon monoxide– Total valence electrons

• 4 + 6 = 10– Bonding pairs

• 10/2 = 5 bonding pairs– Arrange the atoms

• Two atoms are arranged side by side.– Place a bonding pair between the C and O atom– How many pairs remain?

• 5 pairs - 1 pair used = 4 remaining pairs• Add the remaining pairs to the terminal first...then the central.

– Check for multiple bonds. (Does each atom have 8 valence electrons?)

• No, so there ARE multiple bonds needed.

As you come in,• Use your cell phone or a laptop to access the

socrative app. (m.socrative.com)

• Take the practice covalent and acid quiz. You may use a periodic table as the resource.

• Do you have any questions? We’ll be taking the REAL quiz in a few minutes.

• When you have finished the practice quiz, please put your cell phone in the organizer pocket to prepare for the real quiz.

After the quizDraw the following Lewis structures into your notes. Predict the polarity of each.– I2

– SO3

– CF4

– PCl3– SiO2

Advanced Lewis Structures

Draw the Lewis structure for CH3Cl.

– Check the polarity of the overall molecule.– Will this molecule mix with water?

Advanced Lewis Structures

Draw the Lewis structure for silicate.– Check the polarity of the overall molecule.– Will this molecule mix with water?

Advanced Lewis Structures

Draw the Lewis structure for CH3OH.

– Check the polarity of the overall molecule.– Will this molecule mix with water?

VSEPR TheoryThree-dimensional representation of moleculesValence Shell Electron Pair Repulsion TheoryCounting areas of electron density around the central atom.Electron density repels!This bends the molecule into interesting shapes.

Arranging Areas of High E- Density

# regions of high electron

densitymolecular shape

bond angle

2 linear 180°

3 trigonal planar 120°

4 bent <109.5°

4 tetrahedral 109.5°

4 trigonal pyramidal<109.5

°

Predict Shapes & Angles

Go back to the Lewis structures that you drew earlier. Let’s check them and make some predictions.

– I2

– SO3

– CF4

– PCl3– SiO2

Examples to Build at Your Station

1. H2O

2. O2

3. HCl

4. CO2

5. NH3

6. CH4

7. NO3-

8. CH3CH3

Draw a data table of 7 columns.

Column 1 - Formula

Column 2 - Name

Column 3 - Lewis structure

Column 4 - Shape

Column 5 - Bond angle

Column 6 - Polarity

Column 7 - Type of Intermolecular Force

Intermolecular Forces

Abbreviated - IMF

Forces of attraction and repulsion that exist BETWEEN molecules

Three types of IMF:– London dispersion forces– Dipole-dipole forces– Hydrogen bonding

Strength Increasing

Three Types of IMF

London dispersion forces (LDF) - weakest of all intermolecular forces; temporarily exists between any two molecules; ONLY one that occurs in nonpolar molecules (low melting & boiling points)Dipole-dipole forces - forces of attraction/repulsion that exist between POLAR molecules as a result of the partial charges (high melting & boiling points)Hydrogen bonding - STRONGEST intermolecular force that occurs when H is bonded to FON creating REALLY strong partial charges (highest melting & boiling points)