Matter

I. States of Matter
Solid (S), Liquid (L), Gas (G)

• Definite shape — S

• Particles in fixed position — S

• Compressible — G

• Particles have highest energy — G

• No definite volume — G

• Vibrating/rotating motion — S

• Definite volume, no definite shape — L

II. Classify as Element, Compound, Mixture, or Solution

• Barium Chloride (BaCl₂) — Compound

• Lithium — Element

• Chlorine (Cl₂) — Element

• Soda — Solution

• Granite — Mixture

• Windex solution — Solution

• Air — Solution

• Carbon dioxide (CO₂) — Compound

• Oil and water — Mixture

• Paint — Mixture

• Titanium — Element

III. Chemical (C), Intensive Physical (IP), or Extensive Physical (EP)

• Texture — IP

• Flammability — C

• Odor — IP

• Density — IP

• Malleability — IP

• Solubility — IP

IV. Chemical (C) or Physical (P) Change

• Boiling water — P

• Water condensing — P

• Burning a match — C

• Food coloring in water — P

• Silver tarnishing — C

• Sugar dissolving in water — P

V. Phase Changes

• Solid → Gas — Sublimation

• Liquid → Gas — Evaporation

• Liquid → Solid — Freezing

• Gas → Solid — Deposition

VI. True / False

• Heterogeneous mixtures can be separated physically — True

• A solution is a pure substance — False

• An element can be broken down chemically — False

• A compound is homogeneous — True

• Freezing is endothermic — False

• Changes that release energy are endothermic — False

• Seawater can be filtered — False

• Ionic compounds contain 2 nonmetals — False

• Calcium is a metal — True

VII. Evidence of a Chemical Change

• Color change

• Temperature change

• Gas formation (effervescence)

• Formation of a precipitate

Atomic Theory & Scientists

VIII. Scientist Discoveries

• Plum Pudding Model — Thomson

• First to include a nucleus — Rutherford

• First to include electrons — Thomson

• Cathode-ray tube experiment — Thomson

• Gold foil experiment — Rutherford

• Oil-drop experiment — Millikan

• Planetary model — Bohr

• Atomic theory — Dalton

• Discovered the neutron — Chadwick

• Matter described as unbreakable pieces (atomos) — Democritus

IX. Subatomic Particles Order of Discovery

1. Electron

2. Proton

3. Neutron

Charges

• Proton — +1

• Neutron — 0

• Electron — –1

Mass (relative)

• Proton — 1

• Neutron — 1

• Electron — 0

Location

• Proton — Nucleus

• Neutron — Nucleus

• Electron — Electron cloud

Contributes to Mass Number?

• Proton — Yes

• Neutron — Yes

• Electron — No

Contributes to Atomic Number?

• Proton — Yes

• Neutron — No

• Electron — No

Element Table

• Mn

  • Protons: 25

  • Electrons: 25

  • Neutrons: 30

  • Atomic #: 25

  • Mass #: 55

• Na

  • Protons: 11

  • Electrons: 11

  • Neutrons: 12

  • Atomic #: 11

  • Mass #: 23

• Cl⁻

  • Protons: 17

  • Electrons: 18

  • Neutrons: 18

  • Atomic #: 17

  • Mass #: 35

• As³⁻

  • Protons: 33

  • Electrons: 36

  • Neutrons: 42

  • Atomic #: 33

  • Mass #: 75

X. Bohr Model

• Nucleus in center

• Electrons orbit in energy levels (shells)

XI. Thomson Model

• Positive sphere with electrons embedded (plum pudding model)

XII. Average Atomic Mass
90.9% of mass 12
9.1% of mass 14
Calculation:

• (12 × 0.909) = 10.908

• (14 × 0.091) = 1.274
  Average atomic mass = 12.18 amu

Radioactivity

XIII. Radiation Types

• High-speed electrons — Beta

• Positive charge — Alpha

• Can penetrate some matter except metal foil — Beta

• More energetic than X-rays — Gamma

• Pass through several cm of concrete — Gamma

• Helium nuclei — Alpha

• Electromagnetic waves — Gamma

XIV. Fission or Fusion

• Used in nuclear power plants — Fission

• Uses small atoms like hydrogen — Fusion

• Uses large atoms like uranium — Fission

• Neutrons split other atoms — Fission

• Waste product is helium — Fusion

• Only occurs naturally at the Sun — Fusion

• Produces highly radioactive waste — Fission

• Occurs naturally on Earth — Fission

XV. Multiple Choice Not part of Dalton’s Model:

• The atom has most of its mass in the center
  Not part of Thomson’s Model:

• The proton is at the center of the atom

Radioactive Decay

• Atomic number is sum of protons

• Difference between mass number and atomic number = neutrons

• Alpha decay → mass decreases by 4

• Beta decay → atomic number increases by 1

Correct alpha decay equation:

• ²³⁰₉₀Th → ⁴₂He + ²²⁶₈₈Ra

XVI. Nuclear Reactions

• ²⁴₁₃Al → ⁰₊₁e + ²⁴₁₂Mg

• ²⁷₁₂Mg → ⁰₋₁e + ²⁷₁₃Al

XVII. Half-Life Problems Barium-137
12,000 g → 3,000 g
Half-life = 4.2 hours
Thorium-230
Half-life = 2 days
8 days = 4 half-lives
0.40 → 0.20 → 0.10 → 0.05 → 0.025
Remaining mass = 0.025 g

Honors Question – Lithium Isotopes
Average atomic mass = 6.94 amu

• Lithium-6 ≈ 6%

• Lithium-7 ≈ 94%