Back to Electrons . . .

Planetary Model of the Atom:Central Nucleus

with protons & neutronsElectrons in orbits

SchrödingerMathematical Solution to Electron Probability

Spherical orbitals

The Hydrogen AtomOne Electron but

Multiple electron shellsGround State: level closest to nucleus

Organizing Electrons in Shells

Helium with 2 electrons?

Both are placed in Shell #1

Maximum # electrons/shell: 2n2

Atoms with More electrons

Lithium with 3 electronsExtra electron goes into next shell

Shell Organization

n = 1

n = 2

2 e

8 e

The Periodic Table

Johann Dobereiner 1817

TRIADS:Li, Na, K

Mendeleev & Meyer

1868/9Both published versions of a periodic table

of the elements

Mendeleev’s VersionLeft BLANK SPACES

For undiscovered elements:e.g. Germanium

1886

The Modern Periodic Table

Periodicity

Coinage Metals

Noble GasesChemically inert

All gasesProgressively heavier

Electron ConfigurationLi 3 electrons 2 + 1 Valence

Be 4 electrons 2 + 2 Valence

B 5 electrons 2 + 3 Valence

C 6 electrons 2 + 4 Valence

N 7 electrons 2 + 5 Valence

O 8 electrons 2 + 6 Valence

F 9 electrons 2 + 7 Valence

Ne 10 electrons 2 + 8 (filled shell)

Na 11 electrons 2 + 8 + 1 Valence

Periodicity

Ionization EnergySome atoms lose electrons more easily than others

L i Li+ + e-

Cs Cs+ + e-

Periodicity

Electron AffinitySome atoms attract electrons more avidly

Cl + e- Cl-

F + e- F-

How do Atoms Combine?

Ions = Electrically Charged Atoms

Na+ + Cl- NaCl

Salts

•Always contain balanced +/- charges•Lots of possibilities:

Li+Br- Rb+I-

K+F-

Salts

Alkaline Earth atoms & Chalcogens:

Be Be2+ + 2e-

• O + 2e- O2-

• Be2+ + O2- BeO

Bromellite

Salts

Combinations:

Opposite charges must be balanced:

Ba2+ + 2 I- BaI2

2 Rb+ + Se2- --> Rb2Se

What about Carbon?

Carbon has 4 valence electronsIt needs to lose or gain 4 electrons

to achieve Ne electron configuration

Covalent Bonding

Electron “sharing”Electrons are always paired

Atoms seek to achieve an OCTET

Water

H2O = 2 hydrogen and one Oxygen atom

Methane CH4

Carbon = 4 valence electronsHydrogen = 1 valence electron

Ammonia NH3

Nitrogen = 5 valence electronsHydrogen = 1 valence electron

Multiple Covalent Bonds

Shorter and Stronger than single bonds

Carbon Monoxide CO

Water

H2O = 2 hydrogen and one Oxygen atom

Polar Covalent Molecules

DNA’s Hydrogen Bonds

Weak bondsEasily broken but easily reformed

Chlorofluorocarbons (CFC’s)

Synthetic compoundsGood heat transfer agents

Refrigerants; aerosol sprays

Ozone Hole

Ozone = O3Absorbs ultraviolet rays Increase in skin cancer,

& cataracts

Carbon – Chlorine Bonds

Why Antarctica?

•Coldest place on earth

•Polar vortex traps gases

•Ice crystals enhance

reaction

Types 0f Chemical Bonds

Ionic Bonding Covalent Bonding

Salts; electrons lost from oneAtom and gained by anotheratom

Electrons are shared in single (one pair), double (two pairs) or triple (three pairs) bonds.

Metallic Bonding

Loosely held electronsGood conductorsTough materials

Atoms -> Molecules -> Substances

Gases Liquids Solids

Atoms far apartNon-interactiveFast movingNo shapeFormed by liquid evaporation

Atoms closerSome interactionOccupies a defined volumeSolids meltGases condense

Atoms in set arrangementAtoms vibrate but do not translateRigid ShapeStrong interactionLiquid freezes

Crystalline Solids: Carbon

Diamond Graphite

High melting pointExceptional hardness

Lubricating (slippery)

SolidsCrystalline Amorphous

Regular repeating arrangement of atoms

Lacks a regular 3-D pattern

Liquid Crystals

Minerals

Naturally occurring crystalline compound

with a known elemental composition

Silicates (SiO4) Non-silicates

Quartz pyrite

How are minerals formed?

Earth’s Interior

Inner Core: solid nickel/ironOuter Core: liquid

Mantle: SilicatesCrust: thin, rigid

Continental DriftAlfred Wegener

1880 - 1930

Meteorologist

1915 “The Origin of Continents and Oceans”

Pangaea

Plate Tectonics

Evidence:

Mesosaurus fossils

Glossopteris ferns

“puzzle pieces”

Glacial debris

Tectonic Plates

Plate Boundary TypesDivergent Convergent Lateral

Transform

North American and Eurasian plates

Nazca and South American plates

San Andreas fault

Finding the epicenter

Richter ScaleLogarithmic

scale

7.2 quake hasamplitude

10x greater than6.2

30x energy released

The Ring of Fire

Hot Spots

Volcanic Eruptions

Krakatoa 1883

Volcanic Eruptions

Kilauea

Mt St Helens (1980)

Before and after the May 1980 eruption

Mt Redoubt

Alaska 2009

Mt Tambora (1815)

1816

The Year without a Summer

““Darkness” (Lord Byron)

“I had a dream, which was not all a dream.The bright sun was extinguish'd, and the stars

Did wander darkling in the eternal space,Rayless, and pathless, and the icy earth

Swung blind and blackening in the moonless air;Morn came and went--and came, and brought no day”

Volcanoes & Climate

1783/1784:Laki, Iceland

Asama, Japan

Earth’s Atmosphere

Shell of gases circling the Earth

Troposphere

Where all weather systems operate

Densest layer, due to gravity

Stratosphere

Ozone LayerJet stream

IonospherePropagates AM radio signals

(Longer wavelengths)Aurora Borealis (Northern Lights)

Early Earth’s Climate

3 Billion years agoinitially H2 & He

Nitrogen (N2),

Carbon dioxide(CO2)

from volcanoes

PhotosynthesisCO2 + H2O -----> O2 + Glucose

Earth’s current atmosphereN2 78%

O2 20.9%

Ar 0.93 %

CO2 0.038%

Carbon Dioxide Levels

Humidity

Hydrological Cycle

Water Molecules in Air

Volume increases with higher temperatureDensity decreases with temperature

HOT AIR RISES and HOLDS MORE H2O9 g @ 10°C 17 g @ 20°C

30 g @ 30°C

Relative Humidity

Amount of water vapor increasesEXPONENTIALLY With temperature

Saturation Pointmaximum amount of H2O vapor at that temperature

Reached by 1. Excessive evaporation

2. Rapid Temperature drop

Dew

Water condenses as Temperature drops

Night temperatures cooler

FrostIs formed if temperature

approach the freezing point of H2O

(32°F or 0°C)

SF Bay Fog

Cooler ocean air + warm land

Usually late afternoon

Clouds

Weather Systems

Warm front

Ring around the Sun (or Moon)

Means rain on the way

Weather Systems

Cold front

Thunderstorms

Lightning = Voltage Discharge

Hail

Severe Weather

Tornadoes and WaterspoutsWind speeds 60 – 120 mph

Tornado Formation

Tornado Frequency

Tornado Season

Cyclonic Storms

Hurricanes & Typhoons

Hurricane Formation

Warm ocean waters temperatures > 76°F

> 24.4°C

Hurricanes 2005

26 stormsJune -> December

El Nino1997 – 1998 winter

Flooding in N. & S. AmericaRecent drought & fires in Asia

El Nino Southern Oscillation (ENSO)

1982 – 1983 winter

El Nino/La Nina Events

Earth’s climate

The Last Million Years

Climate cycles:Hot House vs. Ice Age

Average: 15° C

The Last Ice Age

Climate Cycles

Orbital variation

Tilt change

Solar flux

Orbital Variations

100,000 year cycles

Obliquity of the Earth’s Axis

Change in the Earth’s Tilt

41,000 year cycle

Greater tilt: Interglacial

Less tilt: Glaciation

Precession26,000 year cycle

Changes in Solar Flux

Sunspots?

25 April 2009

Maunder Minimum

Historic Climate Eras

Medieval Warm PeriodPopulation Boom

Viking Travel

England exported wine

Steppe Drought

The Little Ice AgeGrain production

Ergot Blight

Plague

Patagonianicefields

Climate Cycles

Role Of

CO2

Greenhouse Gases

Greenhouse Gases

Svante Arrhenius

Fuel Burning <-> Global Warming

cutting the amount of CO2 in the atmosphere by half could lower the temperature in Europe by some 4-5 oC.

Greenhouse Gases Sources

CxHyOz + O2 -> CO2 + H2O

Greenhouse Gases

Greenhouse Gas Levels

Venus

800 K temp

90x atmosphere

96% CO2

Global WarmingGlacial Melting

Permafrost thaw

Increased evaporation

Seasonal change

Coral reef bleaching

Glacial Melting

Arctic Ice Cap

Greenland Ice

Antarctic Ice

Sea Level Rising

Imperiled Coastlines

One – Five Meter Sea Level Rise

Consequences

Local Consequences

Increased Evaporation RatesSevere Storms

Coastal Erosion

Fires

Tropical Storm Formation

2005

KatrinaRita

Wilma

Coastal Erosion

Saltwater Intrusion

More Frequent El Niño

1997-8 El Niño

El Niño Frequency

Permafrost Thaw

Coral Reef Bleaching

Wildlife Habitats

Already Extinct

Expanded Pest Ranges

More Pests

Physical ScienceThe Universe Around Us

How does it Work?

What is it made of?

How does it affect us?

Physical ScienceThe Universe Around Us

How does it Work?

What is it made of?

How does it affect us?

How have we affected the world?