1

Adventures of Oxygen Clip

2 GOALS 1. Compare & contrast ionic and covalent bonds electron position. in terms of 2. Predict formulas for stable binary ionic compounds based on balance of charges. 3. Determine the Types of ions formed by representative elements 3. Use IUPAC nomenclature for transition between chemical names and chemical formulas of - binary ionic compounds - binary covalent compounds 4. Apply the Law of Conservation of Matter by

16

the following types of chemical equations: • Synthesis • Decomposition • Single Replacement • Double Replacement balancing

34

3

Why do Atoms Form Compounds?

• Stability.

• What makes an atom stable?

• Full outer energy level.

–Eight.

• They can either…… –1) Gain electrons –2) Lose electrons –3) Share electrons

4

•A Chemical Bond holds

atoms together in a compound.

•Two basic types

:

1. Ionic 2. Covalent

5

Ionic Bonding

Remember: Atoms need a full outer energy level to be stable. EIGHT!

6

Ionic Bonding

OPPOSITS ATTRACT!

7

When Atoms gain or lose electrons, they are called Ions.

3P 3P Anion 3P 3P 3P Cation 3P

• Metals lose electrons to become stable.

• Nonmetals gain electrons to become stable.

8

9

Atoms can gain or lose electrons

Ionization: requires energy Why do atoms lose and gain electrons?

To become more stable.

Stability=full outer energy level

11

OPPOSITS ATTRACT!

12 Properties of Ionic Compounds • Crystalline solids at room temperature.

• Arranged in repeating three dimensional patterns • Have high melting points • Can conduct electricity when melted or dissolved in water

13

14

Covalent Bonding

15

16

Hydrogen and Fluorine Hydrogen and Chlorine

17

Single, Double, Triple

2 e 4e 6e-

Clip 18

19 δ +

Unequal Sharing

Called Polar δ _ Polar molecules happen when one atom has a greater positive charge

20 Properties of Covalent Molecules • Many are gases or liquids at room temperature • Composed of two nonmetals.

• Have low melting and boiling points

• Ionic and Covalent Bonding Review Clip

21

Covalent or Ionic?

(write the formula, then write “C” or “I” 1. CO 3. H 2 O 2 2. NaCl 4. MgCl 2 5. NO 2 6. Li 2 S 7. NaF

clip

9. BeO 10.HCl

11.NaF

12.KCl

13.H

2 O 2 14.N

2 15.Cl

2

Goals revisited

22

• Writing chemical formulas is a shorthand way of indicating what a substance is made of .

• These formulas also let you know how many atoms of each type are found in a molecule.

The chemical formula for water is H 2 O.

Carbon Dioxide is CO 2 .

Why does oxygen combine in different ratios, in different compounds?

The chemical formula for table salt is NaCl. Calcium Chloride is CaCl 2.

Why does chlorine combine in different ratios, in different compounds?

23

The simplest compounds are ones with only two elements These are called binary KI, CO, H

2

O, NaCl

2 4

+1 Oxidation numbers +4 -4

Tell you how many electrons an atom must gain ,

+3

lose

-3 -2

or

-1

share to become stable.

0

25

Oxidation numbers

We can predict the ratio of atoms in ionic compounds based on their oxidation numbers

1 valence electron

+1 K

All compounds

-1 Cl

7 valence electron

Tells you how many electrons an atom must gain, lose or share to become stable.

are neutral

KCl

26

+1 Na NaBr -1 Br +2 Ca -1 Br To make it CaBr 2 Subscripts show the number of atoms of that kind in the compound

27 Now You Try writing Binary Ionic formulas 1.

K + Br 2.

Mg + Cl 3.

Ca + I 4.

K + O 5.

K + I 6.

Sr + Br 7.

Na + O 8.

Ga + Br 9.

Mg + O 10.

Al + P

Some elements have more than one oxidation number (Chart p588)

+3 Fe -2 O +2 Fe -2 O

28

Fe 2 O 3

We call these elements-

FeO

Multivalent Elements

29 Multivalent Practice 1.

2.

3.

4.

Fe +2 Fe +3 + O + O Cu +2 Cr +3 + F + O

30

Polyatomic Ions

Cations: Anions:

ammonium, NH 4 + nitrate, NO 3 Groups of Covalently Bonded atoms that stay together.

sulfate, SO 4 2 hydroxide, OH phosphate, PO 4 3 carbonate, CO 3 2 chlorate, ClO 3 permanganate, MnO 4 chromate, CrO 4 2-

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Try these……

p591 1.

Na + SO 4 2.

Mg + PO 4 3.

Ca + CO 3 4.

Na + OH 5.

Mg + OH 6.

NH 4 + OH 7.

K + PO 4 8.

NH 4 + NO 3 9.

H + SO 4 10.

Ca + SO 4 11.

K + NO 3 12.

Na + PO 4 Mixed Practice

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Naming Binary Compounds and Molecules • Steps: – If it is Binary- 1. Decide if it is an ionic or covalent bond.

– Metal- nonmetal…..

» Ionic – Nonmetal- nonmetal….

» Covalent Example: • NaCl

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If ionic …….

2. Check to see if any elements are

multivalent or polyatomic.

3. If all single valent , write the name of the positive ion first.

4. Write the root of the negative ion and add –ide.

Examples: 1.NaCl

2.K

2 O 3.AlCl

3 4.BaF

2 5.KI

6.Li

2 O

34 If ionic …….

5. Check to see if any elements are multivalent.

6. If multivalent ions, determine the oxidation number of the element.

7. Use Roman numerals in parentheses after the name of the element.

8. Write the root of the negative ion and add –ide.

Examples: 1.FeO

2.Fe

2 O 3 3.CuO

4.Cu

2 O 5.PbCl

4 6.PbI

2

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If it contains a polyatomic ion...

2. Write the name of the positive ion.

3. Write the name of the polyatomic ion.

Examples: 1. NaCO 2. KNO 3. NaC Example: •KOH •Potassium Hydroxide •CaCO 3 •Calcium Carbonate 2 3 H 3 3 O 2

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If Covalent...

2. Use Greek prefix to indicate how many atoms of each element are in the molecule 3. Add -ide to the more electronegative element Example: •NO •Nitrogen Monoxide •PCl 3 •Phosphorous trichloride Greek Prefixes 1- mono 2- di 3- tri 4- tetra 5- penta 6- hexa 7- hepta 8- octa-

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1. KBr 2. HCl 3. MgO 4. CaCl 2 5. H 2 O 6. NO 2 7. CuSO 4 Name the following: Mixed Practice 8. CaSO 4 9. NH 4 OH 10.CaCO

3 11.Cu(ClO 3 ) 2 12.Cr

2 O 3 13. FeO 14. LiBr 15 MgCl

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Goals revisited

39

Chemical Reactions • • A chemical reaction is a change in which one or more substances are converted into new substances.

– Rearrangement of bonds in compounds and molecules.

Chemical Equations make it possible to see clearly what is happening during a chemical reaction

40

Chemical equations are a shorthand way to show chemical reactions.

Reactants Products H 2 + O 2 H 2 O

41

Conservation of Mass

42

H 2 + O 2 H 2 O

2

Conservation of Mass

Hydrogen atoms

Does this meet the

atoms

Law?

2 Hydrogen atoms & one Oxygen atom

Must Balance the Equation to show Conservation of Mass.

43 Can add coefficients to Balance equations.

2 H 2 + O 2 2 H 2 O

2

Balanced!!

Steps: 1. Count Atoms on both sides 2. If not Balanced, add coefficients to balance.

3. Recount atoms after adding each coefficient.

4. Keep adding coefficients until balanced.

44

45

Chemical Reactions • You start with one or more

compounds and turn it into different compounds.

Vapors of hydrogen chloride in a beaker and ammonia in a test tube meet to form a cloud of a new substance, ammonium chloride.

46

1.Synthesis

2.Decomposition

3.Single Replacement

(Single Displacement)

4.Double Replacement

(Double Displacement)

Synthesis

“to make” A + B A B 2H Cu + O Cu O 2

+ O

2

2

H 2

O

Decomposition

“to breakdown” A B A + B 2H 2

O 2

H 2

+ O

2 NaOH Na

+ OH

Animation

Single Replacement

When one element replaces another element in a compound

A

+

B

C

A

C +

B

Cu

+ Ag NO 3

Cu

(NO 3 ) 2 + 2Ag

The more reactive metal will always replace the less reactive metal. (p749)

Single Replacement

• Clip

Double Replacement

Positive Ion of One compound replaces the positive ion of another compound and a Precipitate is formed.

A B +

C D

A

D + C

B Ba (NO 3 ) 2 + K SO 4 2 K NO 3

+

Ba SO 4 Review Clip

Clip

Animation

Review Clip

51 Chemical Reactions and Energy • • All chemical reactions release or absorb energy.

– Heat, light, sound Chemical reactions are the making and breaking or bonds.

1. Exergonic • • Chemical reactions that releases energy are called exergonic .

– Glow sticks If heat is released, it is called exothermic .

2. Endergonic

• • • Chemical reactions that require energy are called endergonic.

Ex: Cold Packs If heat is absorbed, it is called endothermic

•

Catalysts and Inhibitors Some reactions proceed slowly.

They can be sped up by a catalysts .

– –

Catalysts are not used up in the reaction.

EX: enzymes (biological catalysts) Some reactions proceed too fast.

•

They can be slowed down by

–

EX: Preservatives in food inhibitors .

GOALS Revisited…..

1. Compare & contrast ionic and covalent bonds in terms of electron position. 2. Predict formulas for stable binary ionic compounds based on balance of charges.

3. Use IUPAC nomenclature for transition between chemical names and chemical formulas of • binary ionic compounds • binary covalent compounds 4. Apply the Law of Conservation of Matter by balancing the following types of chemical equations: • Synthesis • Decomposition • Single Replacement • Double Replacement