chapter 5 types of compounds ionic compounds covalent compounds lectureplus timberlake1

Chapter 5Types of Compounds

•Ionic Compounds

•Covalent Compounds

LecturePLUS Timberlake 1

Electronegativity (EN)

Def: The strength with which an atom in a bond pulls on e-s.



Covalent Bonds (bonds btwn 2 nonmetals)

Nonmetals have high electronegativity values

(REVIEW)

Electrons are shared

single bond shares 1 pair electrons

double bond shares 2 pairs electrons

triple bond shares 3 pairs electrons


Covalent Bonds

Two nonmetal atoms form a covalent bond because they have less energy (are more stable!) after they bonded

H + H H : H = HH = H2

hydrogen molecule


Learning CheckIndicate whether a bond between the following would be 1) Ionic 2) covalent

____ A. sodium & oxygen

____ B. nitrogen & oxygen

____ C. phosphorus & chlorine

____ D. calcium & sulfur

____ E. chlorine & bromine


Solution

Indicate whether a bond between the following would be 1) Ionic 2) covalent

1 A. sodium and oxygen

2 B. nitrogen and oxygen

2 C. phosphorus and chlorine

1 D. calcium and sulfur

2 E. chlorine and bromine

Types of Covalent (Molecular) Cpds1. Elements that form diatomic

molecules

2. Binary covalent compounds

3. Organic compounds/ Hydrocarbon

4. Acids & Bases

• (Common v. Formal Names)



Diatomic Elements

Elements that exist as diatomic molecules

are : H2, F2, N2, O2, Cl2, Br2, I2

octets

N +

N N:::N

triple bond


Learning Check

Use the name of the element to name a

diatomic molecules.

H2 hydrogen

N2 nitrogen

Cl2 _______________

O2 _______________

I2 _______________


Solution

Use the name of the element to name the

following diatomic molecules.

H2 hydrogen

N2 nitrogen

Cl2 chlorine

O2 oxygen

I2 iodine


Naming Binary Covalent Compounds

Two nonmetals (def of binary covalent)Name each element End the last element in -ideAdd prefixes to show how many atoms of each

(except when there’s only 1 atom of the 1st element listed)

Prefixes-(see Table 5.5, p 168 of text)mon 1 penta 5di 2 hexa 6tri 3 hepta 7tetra 4 octa 8


Learning Check

Fill in the blanks to complete the following names of covalent compounds.

CO carbon ______oxide

CO2 carbon _______________

PCl3 phosphorus _______chloride

CCl4 carbon ________chloride

N2O _____nitrogen _____oxide


Solution

CO carbon monoxide

CO2 carbon dioxide

PCl3 phosphorus trichloride

CCl4 carbon tetrachloride

N2O dinitrogen monoxide


Learning Check

A. P2O5 1) phosphorus oxide2) phosphorus pentoxide3) diphosphorus pentoxide

B. Cl2O7 1) dichlorine heptoxide2) dichlorine oxide3) chlorine heptoxide

C. Cl2 1) chlorine2) dichlorine3) dichloride


Solution

A. P2O5 3) diphosphorus pentoxide

B. Cl2O7 1) dichlorine heptoxide

C. Cl2 1) chlorine

Naming Organic Compounds• Def: organic compounds contain

__ atoms hooked together.

• (Why do you think this element can hook up with many other atoms, including itself?)

Hydrocarbons-A Type of Organic Compound

• Def: hydrocarbons are made of ___ & ___

• They are named by the number of Carbon atoms a molecule contains.

• See Table 5.8, p 183

Table 5.8: Hydrocarbons CH4 methane

C2H6 ethane

C3H8 propane

C4H10 butane

C5H12 pentane

C6H14 hexane

C7H16 heptane

C8H18 octane

C9H20 nonane

C10H22 decane

Common v. Formal Names• Formal Names follow the

rules we have learned for naming compounds.

• Common Names are ones that don’t follow these rules.–Ex: water=

Frequently Used Common Names

• Water = H2O

• Ammonia = NH3

• Common Acids & Bases

Acids & Bases(Table 5.7, p 182)

ACIDSFormula Name

HCl hydrochloric acid

H2SO4 sulfuric acid

H3PO4 phosphoric acid

HNO3 nitric acid

HC2H3O2 acetic acid (vinegar)

Table 5.7 (cont.): BASES

Formula Name

NaOH sodium hydroxide

KOH potassium hydroxide

NH3 ammonia


Covalent Bonds in NH3

Bonding pairs

H

H : N : H

Lone pair of electrons

Allotropes• Def: molecules of the same element that

differ in structure

• Ex: Carbon…graphite, charcoal, Buckminsterfullerine (“bucky ball”)

- see Fig ___ on p ___ of text

• Ex2: O2 (oxygen) and O3 (ozone)

Q:Why do we have to specify the number of atoms of each element in

a covalent compound?

A: Atoms of the same elements can combine in different ratios.

• Ex: C & OCOCO2

Writing Formulas for Covalent Compounds

1. Identify it as a covalent: containing only nonmetals.

2. Determine what type of covalent it is:

diatomic element binary

hydrocarbon (ends in –ane) acid/base

3. Reverse the naming process.


Naming Ionic Compounds•Binary Ionic

• Ionic Compounds contain-ing Polyatomic Ions.

• Ionic Cpds containing Transition Metals


PLEASE NOTE:• IF YOU ARE UNABLE TO

IDENTIFY IONIC & COVALENT COMPOUNDS, YOU WILL BE LOST!!!

• PLEASE SEE ME IMMEDIATELY TO GET CAUGHT UP.



Ionic Bonding & Electronegativity

Nonmetals have high EN’s. Metals have low EN’s.

Bonds between a metal & a nonmetal involve transfers of e-s b/c of the big difference in EN!

Binary Ionic Compounds

•Binary= 2 elements

•Ionic= 1 metal & 1 nonmetal


Naming Binary Ionic Compounds1. Identify & name the 2 elements in the

compound.

2. Name the cation, which is the given the name of the element.

3. Name the anion, which is given the name of the element, w/the ending changed to “–ide.”


PRACTICE Naming Binary Ionic Compounds

1. Na║Cl

2. Na = “sodium”

3. Cl = “chloride”(full name is “sodium chloride”)


PRACTICE Naming Binary Ionic Compounds

1. Li2O

2 & 3.

____║____= ______ ______ (cation (anion (cation name) (anion name)

symbol) symbol)


MORE PRACTICE Naming Binary Ionic Compounds-p __ of I.N.

1. KF

2. CaF2

3. Al2O3


Naming Ionic Compounds w/ Polyatomic Ions

• DEF: Charged particles containing more than 1 type of atom. Ex: SO4

2-



1. Identify the cation & the anion. (Draw a line between the 2 ions)

2. Name the cation, then the anion (find polyatomics on Table 5.3, p 159 of text). That’s it!


PRACTICE :Naming Ionic Compounds w/ Polyatomic Ions

EX: Na2SO4

____║____= ______ ______ (cation (anion (cation name) (anion name)

symbol) symbol)



• Most polyatomic ions are anions.


A Couple of Important Exceptions w/Polyatomic Ions

Important Exception #1: there are 2 cations that contain NO METALS:

NH4+ (ammonium)

H3O+ (hydronium)

(this can be tricky b/c we have always identified ionic compounds because they start with a metal cation.)


A Couple of Important Exceptions w/Polyatomic Ions

Important Exception #2: Some anions contain metals.

Ex: MnO4- = permanganate

Cr2O72- = dichromate

(this can be tricky b/c anions are usually a nonmetal)


Copy Table 5.2 into Notes


Naming Ionic Cpds Containing Transition MetalsEx: NiO2

1.Determine the total # of negative charges in a unit of the compound:

Ex: O2- & O2- = 4 total - charges

2. Determine the charge on the cation that will give you 4 total + charges Ex: Ni4+

3. Write the cation & anion names. Write cation with the oxidation # written as a Roman numeral in parentheses:

Ex: nickel (IV) oxide


Writing Formulas for Binary Ionic Compounds

1. Identify the ionic charge (“oxidation number”) on the cation & anion.



ELEMENT OXIDATION #• Group 1 1+• Group 2 2+• Group 13 3+• Group 14 4+ or 4-• Group 15 3-• Group 16 2-• Group 17 1-


Practice Predicting Oxidation #s

• Li

• O

• Mg

• F

• B



2. A compound has NO CHARGE on it, so a formula unit (the smallest ratio of cations to anions) must have equal numbers of + & - charges. (use the LCM)


Cross-Over Method• You can use this to write formulas.

• Take the charge on the cation and use it as the subscript on the anion

• Take the charge on the anion and use it as the subscript on the cation

• Reduce the subscripts, if necessary


Using the LCM to Write Ionic Formulas

• Ex: Li & F

• Ex: Li & O

• Ex: Al & O


ANSWERS

• LiF

• Li2O

• Al2O3


Writing Formulas for I.Cpds Containing Polyatomic Ions

• Determine the cation & anion• Determine the oxidation # on each ion.

(oxidation #s for polyatomics are found on Table 5.2)

• Write a balanced formula–If there is more than 1 of an ion, use

parentheses, then a subscript


Writing Formulas for I.Cpds Containing Polyatomic Ions

• Ex: see Practice Problems, p 162

3. Write the formula for the compound formed from the following pairs of ions

a) ammonium & sulfite ions

• IONS: NH4+

& SO3 2-

NH4+

• FORMULA: (NH4)2SO3


Practice Problems, cont.from p 16 2of text

3b)

3c)

3d)

4a)

4b)

4c)

4d)


Transition Metals• QUESTION: What was strange about the

e- configurations of transition metals?


ANSWER: Their d sublevels overlap with the other sublevels in the next higher main E.L.

Oxidation #s of Transition Metals

• The d sublevel e-s are so close to the actual valence e-s, they sometimes act like valence e-s!

• See Table 5.4 on p 164 of text: Common Ions of Select Transition Metals

• Ex: Fe 2+ & Fe 3+

• Write the e- configuration


e- Configuration for Fe•Fe=26 e-s

•1s22s22p63s23p64s23d6

•Valence e-s=4s2

•BUT, some 3d e-s can be lost too!


Writing Formulas for Ionic Cpds containing Transition Metals

1. Identify the cation & anion

2. Determine the oxidation #s on the cation & anion

–The oxidation # of the cation is given in the name ex: Nickel (IV) = Ni4+

–The Roman numeral is the oxidation#

3. Write a formula w/ 0 charge.


Distillation• Def: process of separating ionic &

covalent compounds by heating them till the covalent compound evaporates.– The ionic compound remains in the

flask– The covalent compound can be cooled

& collected in a separate container.– This process is called distillation


Learning Check

Match each set with the correct name:

A. Na2CO3 1) magnesium sulfite

MgSO3 2) magnesium sulfate

MgSO4 3) sodium carbonate

B. Ca(HCO3)2 1) calcium carbonate

CaCO3 2) calcium phosphate

Ca3(PO4)2 3) calcium bicarbonate


Solution

A. Na2CO3 3) sodium carbonate

MgSO3 1) magnesium sulfite

MgSO4 2) magnesium sulfate

B. Ca(HCO3)2 3) calcium bicarbonate

CaCO3 1) calcium carbonate

Ca3(PO4)2 2) calcium phosphate


Learning Check

A. aluminum nitrate

1) AlNO3 2) Al(NO)3 3) Al(NO3)3

B. copper(II) nitrate

1) CuNO3 2) Cu(NO3)23) Cu2(NO3)

C. Iron (III) hydroxide

1) FeOH 2) Fe3OH 3) Fe(OH)3

D. Tin(IV) hydroxide

1) Sn(OH)4 2) Sn(OH)2 3) Sn4(OH)


Solution

A. aluminum nitrate

3) Al(NO3)3

B. copper(II) nitrate

2) Cu(NO3)2

C. Iron (III) hydroxide

3) Fe(OH)3

D. Tin(IV) hydroxide

1) Sn(OH)4

chapter 5 types of compounds ionic compounds covalent compounds lectureplus timberlake1

Documents

ionic2 covalent

following names of covalent

covalent bonds bonds

phosphorus chlorine

h h h

sharedsingle bond shares

following diatomic molecules

element listedprefixes