Atom and Valence Electrons Unit Essay

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Chemistry SOL Review
Unit 1: Matter & Measurement-
Classifications of Matter- * Element- contains ONLY ONE type of atom * Compound- TWO or MORE elements joined by a chemical band * Homogeneous- pure substances * Heterogeneous- not evenly mixed substances
Separation Techniques- 1. Filtration- particle size 2. Distillation- Boiling 3. Evaporation- solid remain 4. Chromatography- solubility 5. Centrifugation- Density 6. Magnetism- Magnet
Unit 2: Atomic Structure- 1. Isotopes- Atoms of the same element with different mass numbers
Unit 3: Moles & Nuclear Chemistry-
Half-life Problems- 1. Carbon-14 is used for dating. It has a half-line of 5730 years. If it is the year 2010 and we know a sample has decomposed from 1.00g to 0.125 grams how old is this sample? What year did the sample originate in?

2. How much will of a 10g radioactive sample will remain after 2 minutes when its half-life is only 8 seconds?

Nuclear Chemistry- * Nuclear Reaction- reactions that involve the change in the atomic nucleus * 3 types of radiation 1. Alpha particles (+2)
Ex.) 42He 2. Beta particles (-1)
Ex.) 0-1e 3. Gamma rays (no charge)
Ex.) 00y 4. Positron emission
Ex.) 11p -> 10n+01B 5. Electron capture
Ex.) 11p+0-1e -> 10n * Fission- spits * Fusion- gather to form
Unit 4: Electrons & Electrons Configurations-
Electromagnetic Radiation- 1. Radiowaves 2. Microwaves 3. Infrared light 4. Visible light 5. Ultraviolet light 6. X-rays

1. Red 2. Orange 3. Yellow 4. Green 5. Blue 6. Indigo 7. Violet

1.) What's the frequency of a wave with the wavelength of 50 m?

2.) What's frequency if wavelength equals 5.0*10-8m?

Electron Configuration- * The elements in Group 18 are called the NOBLE GASES because they are STABLE AND tend to be UNREACTIVE (because they have completely filled energy level and 8 valence electrons) * Octet Rule- All elements want 8 valence electrons, will give/take to get 8
Quantum Numbers- n- energy level l- (s=0, p=1, d=2, f=3) ml- from -l to 0 to +l ms- +1/2 or -1/2
Principle States- * Pauli Exclusion- only two electrons per orbital and opposite spins * Aufbau- "to build up". electrons
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