Zumdahl Ch 19, 20, 21 Elements powerpoint

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Chapter 19

The

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Chapter 19

Table of Contents

19.1A Survey of the Representative Elements 19.2 The Group 1A Elements

19.3 The Chemistry of Hydrogen 19.4The Group 2A Elements

19.5The Group 3A Elements 19.6 The Group 4A Elements 19.7 The Group 5A Elements 19.8The Chemistry of Nitrogen

19.9 The Chemistry of Phosphorus 19.10 The Group 6A Elements

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Section 19.1

A Survey of the Representative Elements

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Reviewing the Periodic Table Regions

• Representative elements:

 Groups 1A – 8A (filling s and p orbitals) • _{Transition elements:}

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Section 19.1

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Reviewing the Periodic Table Regions

• Lanthanides and actinides:

 Listed separately, on the bottom of the table (filling 4f and 5f orbitals)

• Metalloids:

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Section 19.1

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The atomic radii of some representative elements (in

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Section 19.1

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Concept Check

Which should be the larger atom? Why?

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Section 19.1

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Concept Check

Which should be the larger atom? Why?

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Section 19.1

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Section 19.1

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Section 19.2

Atomic Masses

The Group 1A Elements

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Section 19.2

Atomic Masses

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Reactions of Group 1A metals

• In the presence of oxygen: 4Li + O₂  2Li₂O

• In the presence of water: 2M_(s) + H₂O_(l)  2M+

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Section 19.2

Atomic Masses

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• In the presence of excess oxygen:

2Na + O₂  Na₂O_2(s) sodium peroxide (contains O₂2-)

K + O₂  KO_2(s)potassium superoxide (contains O₂-)

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Section 19.2

Atomic Masses

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Exercise

Predict the products formed by the following reactants:

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Section 19.2

Atomic Masses

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End of lesson

• See homework on board.

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Section 19.3 The Mole

The Chemistry of Hydrogen

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Hydrides

• (binary compounds containing hydrogen):

 Ionic hydrides:

hydrogen + the most active metals

(ex: LiH, CaH₂)

Note: LiH_(s)+ H₂O_(l) H_2(g) + Li+

(aq) + OH

-(aq)

 Covalent hydrides:

hydrogen + other nonmetals

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Hydrides

 Metallic (interstitial) hydrides:

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Reaction predictions

• Flash cards are strongly recommended for studying reaction predictions. Put reactants on one side and products on the other!

• Try googling “AP Chemistry reaction prediction flashcards”

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Exercise

Predict the products formed by the following reactants:

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Section 19.4

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Alkaline earth metals

• Very reactive

• Great practical importance:

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Section 19.4

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Reactions of Group 2A

• MO_(s)+ H₂O_(l)  M2+

(aq) + 2OH-(aq)

• Ca, Sr, and Ba: • M_(s)+ 2H

2O(l)  M2+(aq) + 2OH-(aq) + 2H2(g)

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Section 19.4

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More reactions of Group 2A (see p. 886)

• M+ X₂  MX₂ where X₂ = any halogen

• 2M + O₂  2MO Ba gives BaO₂ also

• M + S  MS

• 3M + N₂  M₃N₂ • 6M + P₄  2M₃P₂ • M + H2  MH2

• M + 2H+  M2+ + H

2 (meaning M reacts w/ acid)

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Section 19.4

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Ion Exchange

• Ca2+ and Mg2+ are often removed during ion exchange, releasing Na+ into solution.

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Section 19.4

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Section 19.4

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End of lesson

• See homework on board.

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Section 19.5

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• Group 3A elements generally show the increase in metallic character in going down the group

that is characteristic of the representative elements.

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Section 19.5

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Aluminum

• Aluminum is easily oxidized: • Al3+ + 3e-  Al

(s) E ° = -1.66 V

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Section 19.5

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Section 19.6

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• Contains two of the most important elements on earth: carbon and silicon.

• Can form four covalent bonds to nonmetals.

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Section 19.6

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• Si is easily produced from silica sand (SiO₂). • SiO_2(s) + 2C_(s)  Si_(s) + 2 CO_(g)

• Contrast SiO₂ with CO₂:

Network solid; see

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Section 19.6

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Section 19.6

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Section 19.7

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Section 19.8

The Chemistry of Nitrogen

Nitrogen

• N₂ is nonreactive due to the strong triple

bond. This causes most binary compounds containing N to decompose exothermically into the elements:

NO₂(g)  ½N₂(g) + O₂(g)

ΔH° ≈ - 34 kJ

N₂H₄(g)  N₂(g) + 2H₂(g)

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Section 19.8

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Nitrogen reactions

• 3Mg + N₂  Mg₃N₂

• The Haber Process:

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Section 19.8

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Reactions of nitrogen compounds

• NH₃ + H₂O  NH₄+ + OH

-K_b = 1.8 x 10-5

• 2NH₃ + NaOCl  N₂H₄ + NaCl + H₂O • N₂H₄ + H₂O  N₂H₅+ + OH-

base K_b = 8.5 x 10-7

• N₂H₄ + 4OH-  N

2 + 4H2O + 4e -strong reducing agent

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Section 19.8

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Reactions of nitrogen oxides

• NH₄NO_3(s) N₂O_(g) + 2H₂O_(g)

nontoxic, odorless, “laughing gas”

• 2HNO_3(aq)  2NO_2(g) + H₂O_(l) + ½ O₂

• 2NO_(g) + O_2(g)  2NO_2(g)

brown haze of smog

• 2NO₂  N₂O₄

colorless

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Section 19.8

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Reactions involving nitric acid

• Nitric acid is both a strong acid and a strong oxidizing agent.

• N₂O₄ + H₂O  HNO₃ + HNO₂

• 2NaNO₃ + H₂SO₄  2HNO₃ + Na₂SO₄

• Dilute HNO₃ reacts with copper: • 3Cu_(s)+ 8H₃O+

(aq) + 2NO3-(aq)  3Cu2+

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Section 19.8

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Reactions involving nitric acid

•Concentrated HNO₃ reacts with copper: •Cu_(s)+ 4H₃O+

(aq) + 2NO3-(aq)  Cu2+

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Section 19.8

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Nitrogen fixation

• The process of transforming N₂ to other nitrogen–containing compounds.

N₂(g) + 3H₂(g)  2NH₃(g)

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Section 19.8

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Section 19.8

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Nitrogen oxides

• In nitrogen oxides, N has oxidation states from +1 to +5.

• In other compounds, N has oxidation states of -1 to -3.

Compound

Oxidation state of N

N

2

O

+1

NO

+2

N

2

O

3

+3

NO

2

+4

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Section 19.8

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Reactions of nitric and nitrous acid

• Nitric acid, HNO₃

• Nitrous acid, HNO₂

3 2 2 2

4HNO ( ) _l hv 4NO ( ) + 2H O( ) + O ( )_g _l _g

+

2 2

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Section 19.9

The Chemistry of Phosphorus

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Allotropes of phosphorus

• White phosphorus = P₄ (tetrahedral) - very reactive

• Black phosphorus = crystalline structure - much less reactive

• Red phosphorus = amorphous with P₄ chains

heat, 1 atm, no air

(white) (red)

P  P

high pressure

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Section 19.9

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Allotropes of phosphorus

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Section 19.9

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Phosphorus oxyacids

• phosphoric acid, H₃PO₄ • phosphorous acid, H₃PO₃

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Section 19.9

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How is phosphorus obtained?

• 2Ca₃(PO₄)_2(s)+ 10C_(s)+ 6SiO₂ _(s) P_4(g)+ 10CO_(g) + 6CaSiO_3(s)

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Section 19.10

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• O, S, Se, Te, Po

• Although in Group 6A there is the usual

tendency for metallic properties to increase going down the group, none of the Group 6A elements behaves as a typical metal.

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Section 19.11

The Chemistry of Oxygen

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Oxygen

• O₂ is present in both crust (minerals) and in the atmosphere (obviously).

• O₃ (ozone) exists naturally in the upper

atmosphere of the Earth; a less stable allotrope.

• Ozone layer absorbs UV light and acts as a screen to prevent it from penetrating to the Earth’s

surface.

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Section 19.11

The Chemistry of Oxygen

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Ozone

3O

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Section 19.12

The Chemistry of Sulfur

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Section 19.12

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Section 19.12

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Reactions involving sulfur compounds

• 2ZnS(s) + 3O₂(g)  2ZnO(s) + 2SO₂(g)

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Section 19.12

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Sulfur oxide reactions

2SO₂(g) + O₂(g)  2SO₃(g)

Colorless, toxic; Choking odor

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Section 19.13

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Halogens

• All nonmetals: F, Cl, Br, I, At

• Because of their high reactivities, the halogens are not found free in nature. They are found as halide ions (X–) in minerals and in seawater.

• Cl is a yellow-green gas formed from NaCL. • Cl forms many oxyacids (see p. 928.)

• 2NaCl + H2SO4  Na₂SO4 + 2HCl

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Section 19.13

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Section 19.13

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Preparation of Hydrogen Halides

H₂(g) + X₂(g)  2HX(g)

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Section 19.13

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Halogen oxyacids and oxyanions

• All halogens except fluorine combine with

various numbers of O atoms to form a series of oxyacids.

• The strengths of these acids vary in direct

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Section 19.14

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Noble Gases

• He and Ne form no compounds.

• Kr and Xe have been observed to form chemical compounds:

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Section 19.14

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Section 19.14

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Concept Check

Which of the following groups is the most

reactive?

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Section 19.14

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Concept Check

Which of the following groups does not contain at least one element that forms compounds

with oxygen?

a) Group 4A Elements

b) Group 5A Elements

c) Group 6A Elements

d) Group 7A Elements

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Section 19.13

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Objectives:

• Students will know the characteristics of transition metals and their compounds.

• Students will know how to name these compounds.

Chapter 21

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Section 19.13

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Transition metals

• Transition metals are similar within a period. • > 1 oxidation state is possible.

• Compounds are colorful due to light absorption by a partially filled d sublevel.

Chapter 21

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Section 19.13

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Coordination compound =

Coordination complex (complex ion) +

Chapter 21

Coordination compounds

Counter ion

Transition metal ion [Lewis acid]

Ligand (attached molecules or

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Section 19.13

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Coordination compounds

[Co(NH₃)₅Cl]Cl₂

Chapter 21

Coordination compounds

T.M. ion Ligands Counter ions

Note: Co has an oxidation state of +3.

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Section 19.13

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Ligands

Chapter 21

Ligands Anionic ligands names Neutral ligands names

Br- bromo NH

3 ammine

F- fluoro H

2O aqua

O2- oxo NO nitrosyl

OH- hydroxo CO carbonyl

CN- cyano H₂NCH₂CH₂NH₂ ethylenediamine

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Section 19.13

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Monodentate ligands

Chapter 21

Ligands

Bidentate ligands

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Section 19.13

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Naming coordination compounds

Chapter 21

Ligands

Go over rules on p. 958.

Go over examples on p. 958. Example 21.1

Fe₄[Fe(CN)₆]₃

iron (III) hexacyanoferrate (II)

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Section 19.13

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Naming coordination compounds

Chapter 21

Ligands

Try this one:

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Section 19.13

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End of lesson

Chapter 21

Ligands