What is simplified in this picture?

TheThompson: Discovery of the Electronthe Electron (Thomson)

• Cathode Ray Tube

• Charged particles produced (affected by magnetic field)

• Concluded that atom must have positive and negative parts

• Electron – negative part of the atom

• Only knew the e/m ratio

• Plum Pudding Model

Charge and Mass of the Electron (Millikan)

• Oil drop experiment

• Determines charge on electron (uses electric field to counteract gravity)

• Quantized

• e = 1.602 X 10-19 C

• m = 9.11 X 10-31 kg

The Nucleus (Rutherford)

• Gold Foil Experiment

• Discovers nucleus (disproves Plum Pudding Model)

• Planetary Model

Three particlesParticle Charge Mass

Proton +1 ~1 g/mol

Electron -1 0.00055 g/mol

(1/1837)

Neutron 0 ~1 g/mol

Atoms:Basic Facts

Photo of a single Barium atom

1. Size – Measured in Angstroms

1 A = 1 X 10-10 m

1 Cl atom = 2.0 A

5 million Cl atoms can be lined up in 1 mm.

Atoms:Basic Facts

1. Mass – grams/mole

H = 1.00794 grams/1 mole

1.00794 g/6.022 X 1023 atoms

C = 12 g/mol

Atoms:Basic Facts

1. Isotopes – Atoms with the same # of protons, but different # of neutrons

Copper-63 29 p 34 n

Copper-65 29 p 36 n

2. Atomic Mass –weighted average of all the isotopes

Isotopes

p n E

13C90Sr

24Mg

16 16

16 18

16 16 18

12 12 10

17 19 18

1. Cation – Positive Ion

2. Anion – Negative Ion

3. Review Common Charges

Ions

P N E

Cl-

O2-

Mg+

Mg2+

Stable vs. Unstable Nuclei

1. Most nuclei are stable – do not change

2. Some nuclei are unstable (radioactive)• Change into a different nucleus (decay)• Spontaneous process – happens naturally, by itself• Releases radiation

Only nuclear reactions can change a nucleus.

No chemical process can

Nuclear Changes

Radium Radon + Radiation

Decay

-New element and alpha, beta, or gamma

-lost mass becomes kinetic energy

Types of Nuclear RadiationAlpha particle

(42He)

Helium nucleus

Beta particle

(0-1e)

fast-moving electron.

Gamma rays

high energy electromagnetic radiation

Positron

(0+1e)

positive electron (anti-matter)

2 p+

2 n

e-

What Stops Radiation

Paper Al Foil

Wood

Lead.

Iron,

Concrete

Alpha ()

Beta ()

Gamma ()

Decay Equations

Alpha Decay238

92U 42He + 234

90Th

Beta Decay 234

90Th 0-1e + 234

91Pa

Decay Equations

Gamma Decay

Occurs with alpha and beta decay

No change in atomic mass (gamma radiation has no mass 0

0)

Decay: Ex 1

What product is formed when radium-226 undergoes alpha decay?

22688Ra 4

2He +

Decay: Ex 2

What element undergoes alpha decay to form lead-208?

42He + 208

82Pb

Decay: Ex 3

What isotope is produced when thorium-231 beta decays?

23190Th 0

-1e +

Write the equation that describes oxygen-15 undergoing positron emission.

Which nuclei are radioactive (unstable)1. All elements have at least one radioactive

isotope

2. All isotopes of elements heavier than Lead (82)

82

Pb

207.2At least one radioactive isotope

All isotopes are radioactive

Transmutation

• Rutherford(1919) – First successful alchemist14

7N + 42He 17

8O + 11H

• Modern methods– Particle Accelerators (Cyclotrons)– Use neutrons or other elements (creation of

transuranium elements)

1. Dmitri Mendeleev – 1869

2. Used atomic mass (modern is by atomic #)

3. Period – Across

4. Group – Down

5. Metals

Non-Metals

Metalloids - Semiconductors

Periodic Table

Group 1 Alkali metalsGroup 2 Alkaline earth metalsTransition MetalsGroup 7 HalogensGroup 8 Noble GasesLanthanidesActinides

Discuss placement of Lanth/Act

Periodic Table

Average Atomic Mass

1. Atomic Mass – Weighted Average of all the isotopes

Calculate the ave atomic mass of Boron if it exists as 19.90% Boron-10 (10.013 g/mol) and 80.10% B-11 (11.009 g/mol)?

(Ans: 10.811 g/mol)

Average Atomic Mass

Ionic = Metal + Non-metal (NaCl)

Molecular = Non + Non (CH4)Alloy = Metal + Metal

•Stainless steel (Fe/Cr)•Brass (Cu/Zn)•Bronze (Cu/Sn)

Mixing Elements

Ionic vs. Molecular

Ionic Compounds Molecules

Start w/ MetalStealing of ElectronsClumps of Ions(crystals)Called Salts

No prefixes, may need Roman #

Two Non-metalsSharing of electronsSeparate MoleculesShapes (tetrahedral, etc…)Polar and Non-Polar Molecules (H2O vs CH4)

Prefixes

Ionic Solids

Ionic or molecular?

HCl

CO2

VO3

H2O

BaF2

Ionic vs. Molecular

What ionic compound would form between:

Ba and Cl

Ba and Te

Al and S

Fe3+ and O

Fe2+ and O

H He

             

    Al    

                             

           

                                   

Naming IonicsI. Binary CompoundsGr I and Gr II metals (and Aluminum)NaClBaO

Al2O3

magnesium bromidealuminum sulfidepotassium oxide

I. Compounds with Polyatomics

Sodium hydroxide

Sodium carbonate

Aluminum Sulfate

NaNO3

Ca(OH)2

(NH4)3PO4

Naming Ionics

Mixed Examples

Magnesium Sulfide

Magnesium Sulfite

Magnesium Sulfate

Lithium Phosphide

Lithium Phosphate

Ba(ClO3)2

BaCl2

Roman # Ionics

1. ExampleFe(II)and oxygenFe(III) and oxygenHow do we distinguish?

2. Metals which have multiple oxidation statesTransition and post-transition metals

Iron (III)Bromide

Tin(II) nitrate

Cobalt(III)Oxide

CoCl2

MnO2

Ru2(SO4)3

VO3

Mixed ExamplesCalcium BromideChromium (III)NitrateAluminum SulfateIron(III)Carbonate

Li2S

CoCl2

Ti3N2

Mg(NO2)2

Magnesium Sulfide

Magnesium Sulfite

Magnesium Sulfate

Mn2(SO4)3

Lithium Phosphide

Lithium Phosphate

Ba(ClO3)2

Copper(II)nitrate

Household Ionics

Many ionic compounds are called salts

CaCl2 – Calcium Chloride (Quik-Joe)

NaHCO3 – Sodium bicarbonate(Baking soda)

CaCO3 – Calcium Carbonate(Chalk, antacid)

NaOH - Sodium Hydroxide (Drano)

MgSO4 – Magnesium Sulfate(Epsom Salts)

All big clumps (crystals) of Ions

Naming Molecules

Prefixes

mono hexa

di hepta

tri octa

tetra nona

penta deca

May skip “mono” for first element

CO

CO2

Cl2O7

SF6

Chlorine dioxide

Diphosphorus tetroxide

Carbon tetrachloride

Naming Molecules

Household Molecules

H2O

HCl

NH3

H2SO4

HC2H3O2

Review of all naming

CS2 N2O

NaI PCl5

FeF2 HgI2

K2CO3 NO3

Ba(OH)2

Calcium Chloride

Silicon Dioxide

Copper(II)Carbonate

Magnesium Phosphate

Dicarbon Octahydride

Chromium(III)Oxide

Dihydrogen Monoxide

Acids

1. Binary Acids

HCl hydrochloric acid

HF hydrofluoric acid

H2S hydrosulfuric acid

Acids

2. Oxoacids

Acid Ion

HClO4 perchloric acid perchlorate (ClO4-)

HClO3 chloric acid chlorate (ClO3-)

HClO2 chlorous acid chlorite (ClO2-)

HClO hypochlorous acid hypochlorite (ClO- )

Examples

HCN

HNO3

H2SO4

H2SO3

Examples

HNO2

HI

H3PO4

H3CO3

HClO3

H2 Hydrogen (H- Hydride)

N2 Nitrogen(N3- Nitride)

O2 Oxygen (O2- Oxide)

F2 Fluorine (F- Fluoride)

Cl2 Chlorine (Cl- Chloride)

Br2 Bromine (Br- Bromide)

I2 Iodine (I- Iodide)

26

1)Xe-130 has one more neutron

50)

1)Molecular PF5, SCl, N2O4

Ionic NaI Ca(NO3)2, FeCl3, LaP, CoCO3

32. 85.47 g/mol56.a) CuBr2 b) Fe2O3 c) Hg2CO3

d) Ca3(AsO4)2 e) (NH4)2CO3

58. Na2O CaO FeO Al2O3

NaNO3 Ca(NO3)2 Fe(NO3)2 Al(NO3)3

Na2SO4 CaSO4 FeSO4 Al2(SO4)3

Na3AsO4 Ca3(AsO4)2 Fe3(AsO4)2 AlAsO4

64.a) Cu2+ b) Ag+ c) Al3+ d) Co2+

e) Pb2+

1. 85.47 g/mol

2. Cu2+ S2-

Ag+ SO42-

Al3+ ClO3-

Co2+ OH-

Pb2+ CO32-