Bellwork: Monday 4/9/2012 Naming Covalent Compounds 1. 1. F 2 Fluorine gas 2. 2. Cl 2 Chlorine gas...

Bellwork: Monday 4/9/2012Naming Covalent Compounds1. F2

Fluorine gas2. Cl2

Chlorine gas3. HF

Hydrogen fluoride

4. HCl Hydrogen

chloride5. H2S

Dihydrogen sulfide

6. NO Nitrogen

monoxide7. NO2

Nitrogen dioxide8. NO3

Nitrogen trioxide9. N2O

Dinitrogen monoxide

Naming Covalent Compounds- pg 5Formulas to Names Names to Formulas

1. Silicon tetrachloride2. Carbon disulfide3. Tetraphosphorus

pentasulfide4. Phosphorus trihydride5. Antimony tribromide6. Disilicon hexabromide7. Carbon tetrafluoride8. Dinitrogen trioxide9. Sulfur hexachloride10. Sulfur trioxide

1. B2H6

2. ClO2

3. NBr3

4. SeF6

5. XeF6

6. B6Si

7. BF3

8. NF3

9. P2O5

10.SiF4

Review: Classifying Chemical Bonds Covalent bonds are those

between non-metals and non-metals

Ex: C (non-metal) and H (non-metal) CH4

Ionic bonds are those between metals and non-metals

Ex: K (metal) and O (non-metal) K2O

Metallic bonds are those between metals and metals

Si

As

Al

Ge

Sb

Po

B

Te

At

HH Metalloids

(dual properties)

METALS vs NON-METALS

Understanding how ions react to other elements will help in naming

compounds or coming up with formulas for the compounds.

Opposite charges attract! Same charges

repel!

2e-

3p+4p+

LiBeB

5p+6p+

CTo become happy…

Get more?

OR

Get rid of ‘em?

I

II III VIVIV

+1 +

2+3 -4

VII VIII

What is the charge?

+4

2e-

NOF

7p+8p+9p+10p+

Ne

8e-

Na

11p+

I

II III VIVIV

+4

+1 +

2+3 -4 -2

-1

-3

0VII VIII

To become happy…

Get more?

OR

Get rid of ‘em?

What is the charge?

2e-

4p+

Be

2e-

F

9p+

I

II III VIVIV

+4

+1 +

2+3 -4 -2

-1

-3

0VII VIII

+2 -1

2e-

4p+

Be+

22e-

F-1

9p+

2e-

F-1

9p+

I

II III VIVIV

+4

+1 +

2+3 -4 -2

-1

-3

0VII VIII

Beryllium fluorideBeF2

Al+3

Cl-1Cl-1

Cl-1

Al+3

Cl-1

I

II III VIVIV

+4+1

+2

+3 -4 -2-1

-30

VII VIII

AlCl3Aluminum chloride

Ionic Bonding- Page 7 Ionic Bonding- Bond between metal and non-metal

Transfer of electrons, which results in positive or negative charged ions that attract to each other (opposites attract)

The greater the charge, the greater the attraction

Oxidation number- how many electrons an atom has gained, lost, or shared to become stable; the charge (+ or -)Cation- When an atom loses an e-, it loses a negative

charge & becomes a positive ion.Anion- When an atom gains an e- it gains a negative

charge & becomes a negative ion.

Lithium Calcium Chlorine Seleniu

m Arsenic

Li+1

Ca+2

Cl-1

Se-2

As-3I

II III VIVIV

VII VIII

1 2 7 6 5

Lose 1 e’ Lose 2 e’ Gain 1 e’ Gain 2 e’ Gain 3 e’

Element Name

# of Valence e’

How it’s going to get

happy

Ion it would form

Ionic compounds are electrically neutralGoal: Balance out the chargesSum of all oxidation numbers in compound = ZERO

Ex: Magnesium and Chlorine = Magnesium chlorideWhat is the charge of Chlorine? Magnesium?How many chlorine ions are needed to balance

the magnesium ions?

2 Cl-1

ions balance 1 Mg+2

ion

Mg+2Cl-1

2

•Mg loses 2 electrons to become stable, becoming positively charged Mg+2

•O gains the 2 electrons to become stable, so O becomes negatively charged O-2

Mg O Mg+2O-2+2 -2

Magnesium oxide

Br

Ni

Occasionally, you may need more than just one atom to fulfill each atom’s Octet rule…

Br

Br

Ex: Ni + Br =

Nickel (III) bromide

Ni Br+3

-1

3

“+3” tells that Nickel has lost 3

e-s to become

(+)

“-1” tells that each Bromine

atom has gained 1 e- to

become (-)

“3” tells that 3 Bromine atoms are needed to

stabilize 1 atom of Nickel

Ionic bonding: Al + Cl

Al+3 Cl3–1

Cl

Al Cl

Cl

Aluminum chloride

NOW: Try it yourself on pages 7 & 8!

Bellwork:

Tuesday 4/10/20

12

Mg & Cl Al & Cl1. Draw a diagram to show how they ionically

bond to form neutral compounds.2. What is the formula? What is the name?

Magnesium chloride

Mg+2Cl2-1

Al+3 Cl3-1Aluminum chloride

K+1F-1

Na2+1 O-2

Be+2 S-2

Mg+2 I2-1

B+3 F3-1

Al+3Br3-1

K2+1

1

S-2

Ca2+2 Si-4

Al2+3O3-2

Mg3+2 N2-3

Naming Simple Ionic Compounds- Pg 8

When writing the name of ionic compounds:

The first atom listed… Is the cation (+)Is capitalized Is written as the name of that element

The second atom listed…Is the anion (-)Is written in lowercaseIs shortenedEnds in the suffix “-ide”

Ex: Fe2O3

…is Iron oxide

+3 -2

1) NaBr

2) CaO

3) Li2S

4) MgBr2

5) Be(OH)2

Sodium bromide

Calcium oxide

Lithium sulfide

Magnesium bromideBeryllium hydroxide

Writing Ionic Names to Formulas

When writing an ionic compound’s formula, you need to find the following:The atomic symbols for each elementOxidation Numbers - *Remember: these tell

you how many of each atom you need!○ *NOTE: If the Oxidation Numbers are the

same, you DO NOT need to write them anywhere in the formula!

ADD this example at the bottom of the “Names to Formulas” Table!Calcium oxide Ca

+2

CaOO-2

Now let’s try to write the chemical symbols for each compound

1) Potassium iodide

2) Magnesium oxide

3) Aluminum chloride

4) Magnesium hydroxide

5) Calcium Oxide

KI

MgOAlCl3

Mg(OH)2

K+1

O-2Mg+

2

Cl-1Al+3

OH-

1

Mg+

2

I-1

Ca+

2

O-2 CaO

Naming Complicated Ionic Compounds: Metals that form MORE THAN ONE IONPeriodic Chart of Ions- Page

11What ions does Iron (Fe)

form? Ions: Fe+2 or Fe+3

Use roman numerals for charge○ Fe+2 = Iron (II)○ Fe+3 = Iron (III)

Roman numera

l

Charge

I +1II +2III +3IV +4V +5VI +6

Assume you need a roman numeral for all metals, except:Metals in group I and IIAluminum (Al), Cadmium

(Cd), Silver (Ag), and Zinc (Zn)

Naming Complicated Ionic Compounds:

POLYATOMIC IONS “more than one atom” ions

Common Polyatomic Ions- Page 9 Ions made up of two or more atoms Made of two non-metals

Covalently bonded together When they bond with another ion, an ionic bond

forms Think of them as a group of atoms that react as ONE!

Remember: CO and Co are different! The second letter of an atomic symbol is always lowercase

Naming Ionic Compounds

1st Word: Name the cation (positive ion)Usually the full name of the

metal 2nd Word: Name the anion

(negative ion)Element:

○ 1st syllable; ends in “-ide”Polyatomic Ion:

○ Unchanged name of polyatomic ion

Does the metal have a Fixed Oxidation Number?FIXED- NO roman numeral is

used○ You know the charge of the

fixed ions!! (Group 1, 2, 13, etc.)

FORMS MORE THAN ONE ION- YES use roman numeral○ Charge expressed as roman

numeral, in parenthesis, after the name of the metal

CaSO4Ca?SO4

-

2Ca+2

sulfateCalcium

Fixed oxidation number

Naming Ionic Compounds

1st Word: Name the cation (positive ion)Usually the full name of the metal

2nd Word: Name the anion (negative ion)Element:

○ 1st syllable; ends in “-ide”Polyatomic Ion:

○ Unchanged name of the polyatomic ion Does the metal have a Fixed Oxidation

Number?FIXED- NO roman numeral is used

○ You know the charge of the fixed ions!! (Group 1, 2, 13, etc.)

FORMS MORE THAN ONE ION- YES use roman numeral○ Charge expressed as roman numeral, in

parenthesis, after the name of the metalThe oxidation number on the negative ion

determines the charge on the positive ionTotal oxidation state must be zero

○ Positive charge must equal the total negative charge

○ A simple algebraic equation can be used to determine

CuSO4Cu?SO4

-

2x + (-2) = 0

sulfateCopper

x = 2

(II)

Examples #1- Formulas to Names

CuSO3

Copper

I’m a polyatomic

ion

1. Write the names of the ions

Final Namesulfite(II)

x

X + (- 2) = 0

X = +2

Cu SO3

= 0You must know the charge on the sulfite

ion is -2

The sum of the positive and negative charges

must equal zero

2. Determine the charge of the positive ion

-2

+2 +2

+2


KMnO4

Potassium

I’m a polyatomic

ion


Final Name permanganate

If the positive ion has a fixed charge, you are finished.


NH4NO

3

Ammonium

I’m a polyatomic

ion



Final Name nitrate


I’m a polyatomic

ion


SnF2

Tin



Final Name fluoride(II)

Snx (F-1)2 = 0

X + 2(-1) = 0

X = +2


Ba(ClO4

)2Barium

I’m a polyatomi

c ion



Final Name perchlorate



Cu2

SCopper

I’m NOT a polyatomic

ion



Final Name sulfide(I)

2Cux S-2 = 0

2X + (-2) = 0

X = +1


Na2Cr2O

7

Sodium

I’m a polyatomic

ion



Final Name dichromate

If the positive ion has a fixed charge, it is not shown


LiCN

Lithium

I’m a polyatomic

ion



Final Name cyanide


Writing Names to Formulas It is easier to write

the formula of an ionic compound from its name than the reverse.

But, you must know the oxidation number of the ions!Refer to the table of common polyatomic ions

Example #1-Names to Formulas

Aluminum chloride

Al Cl3

2. Determine number of ions

1. Write symbols of elements

Final Formula

x(+3) + y(-1) = 0

1

If there is only one atom the “1” is not shown

+3(Al )x(Cl-1)y

1(+3) + 3(-1) = 0

This formula says that the +3 charge of one Alatom will cancel the-3 charge from 3 Cl atoms


Cobalt (II) bromate

Co BrO3



Final Formula

(Co+2)x(BrO3-1)y

= 0

2X = 1yX(+2) + y(-1) = 0

X 1Y 2=

1Choose the

lowest set of integers

thatsatisfies the

equation


( )2


Nickel (III) acetate

Ni C2H3O2



Final Formula

(Ni+3)x(C2H3O2-1)y

= 0

3X = 1y

X(+3) + y(-1) = 0

X 1Y 3=

1Choose the

lowest set of integers

thatsatisfies the

equation

( )3



Lithium phosphate

Li PO4



Final Formula

(Li )x(PO4-3)y

= 0

1X = 3y

X(+1) + y(-3) = 0

X 3Y 1=

3

+1

( )1


What do you notice about the numbers in the formula for NiBr3?

When criss-crossed, they are equal! The top numbers for each atom are called its

Oxidation NumberThe oxidation number tells you how many electrons

an atom has gained, lost, or shared to become stable The sum of the product of the “oxidation

numbers” and the product of the “# of atoms” in the compound must equal zero

Ni Br+3 -1

3(1)

(3 × -1) + (1 × 3) = 0

http://www.promotega.org/UGA06004/vocabulary.html

http://www.promotega.org/UGA06004/vocabulary.html

The oxidation numbers may be may be criss- crossed to create subscripts in the formula, and used to help write the chemical formulas

This is called the “Criss-Cross Method”

For example: when creating “Aluminum oxide”Aluminum has an oxidation number of +3 Oxygen has an oxidation number of -2 When you cross them… …you find the formula for Aluminum Oxide is Al2O3

Al O Al O+3 -2

+2 32 3

The criss-cross method tells how many of each atom are needed to satisfy each atom’s valence shells

Ex: Aluminum + Oxygen

Al O2 3Oops! Now “O” has extras…Need another

“Al”!

Hmm… We still have more

electrons…we must need

another Oxygen!

Still more electrons? We

must need another Oxygen!

FINALLY!!! We’re done.

Al O+3 -2

+2 3

Try to use the Criss-Cross Method to find the formulas for the following situations:

Calcium + Silicon

Sodium + Bromine

Boron + Fluorine

Potassium + Sulfur

Ca+2

+Na+1 +

B+3 +K+1 +

Si-4 Ca4Si2

NaBrBr-1

F-1 BF3

S-2 K2S

Names to Formulas: Criss-Cross Method

Barium nitrate1. Write the formulas for the cation and anion, including CHARGES! Ba2+ NO3

-

2. Check to see if charges are balanced.

3. Balance charges, if necessary, using subscripts. Use parentheses if you need more than one of a polyatomic ion. Use the criss-cross method to balance the subscripts.

Not balanced!

( ) 2Now balanced.

= Ba(NO3)2

Iron (III) chloride

Fe3+ Cl-

Not balanced!

3Now balanced.

= FeCl3


1. Write the formulas for the cation and anion, including CHARGES!



Ammonium sulfate

NH4+ SO4

2-

Not balanced!

( )2

Now balanced.

= (NH4)2SO4





Aluminum sulfide

Al3+ S2-

Not balanced!

2 3Now balanced.

= Al2S3





Bellwork: Monday 4/9/2012 Naming Covalent Compounds 1. 1. F 2 Fluorine gas 2. 2. Cl 2 Chlorine gas...

Documents

Transcript of Bellwork: Monday 4/9/2012 Naming Covalent Compounds 1. 1. F 2 Fluorine gas 2. 2. Cl 2 Chlorine gas...