Study Topics Summary

States of Matter

• Solid: Tightly packed particles with a definite shape and volume; have strong intermolecular forces.

• Liquid: Particles that move past each other; definite volume but take the shape of their container; intermolecular forces are weaker than solids, allowing for fluidity.

• Gas: Particles that are far apart and move freely; fills the shape and volume of the container; negligible intermolecular forces.

Properties of Matter

• Extensive Properties: Depend on the amount of matter present (e.g., mass, volume, total energy).

• Intensive Properties: Independent of the amount of matter present (e.g., density, boiling point, color).

Types of Changes

• Physical Change: Does not alter the chemical identity of a substance (e.g., cutting, dissolving); may involve a change in state (e.g., melting, freezing).

• Chemical Change: Results in the formation of new substances with different properties (e.g., combustion, oxidation, digestion); involves breaking and forming of chemical bonds.

Mixtures vs. Pure Substances

• Mixture: A physical combination of two or more substances, which can be separated (e.g., oil & water, air).

• Pure Substance: Consist of only one type of particle and have a constant composition; separable only by chemical processes (e.g., CO₂, H₂O).

Separation Techniques

• Magnet: Used to separate magnetic materials (e.g., iron).

• Dissolving: Salt can dissolve in water, separating it from sand.

• Filtration: Separates solids from liquids using a filter.

• Evaporation: Can separate dissolved salts from water by heating until water evaporates.

Atomic Models

• J.J. Thomson: Proposed the plum pudding model where electrons are embedded in a positively charged 'soup' (cathode ray tube experiment).

• Ernest Rutherford: Introduced the nuclear model of the atom, discovering the nucleus (gold foil experiment).

• John Dalton: Proposed an early atomic theory based on solid spheres (Dalton’s atomic theory).

• Niels Bohr: Developed a planetary model of the atom, suggesting electrons exist in fixed orbits (energy levels) around the nucleus.

Calculations

• Density: Calculated using the formula (d = m/v), where d = density, m = mass, v = volume.

• Volume: Can be calculated using (v = m/d).

• Mass: Can be calculated using (m = d × v).

• Unit Conversions: Important for converting between various units (e.g., cm to m, g to kg, mL to L).

Electromagnetic Spectrum

• Order: Ranges from gamma rays to radio waves (Gamma rays → X-rays → UV → Visible → IR → Microwaves → Radio).

• Frequency and Energy: Increases from radio to gamma rays; shorter wavelengths correspond to higher frequencies and energy.

Electron Configurations

• Example: Phosphorus (atomic number 15) is represented as 1s² 2s² 2p⁶ 3s² 3p³, indicating the distribution of electrons across its orbitals.

Periodic Table Trends

• Atomic Radius: Generally increases down a group due to added energy levels and decreases across a period due to increasing nuclear charge.

• Ionization Energy: Energy required to remove an electron; decreases down a group and increases across a period.

• Electronegativity: Measure of an atom's ability to attract electrons; decreases down a group and increases across (with fluorine being the highest).

• Atomic Mass: Increases both down a group and across a period due to the addition of protons and neutrons.

Valence Electrons & Families

• Alkali Metals: 1 valence electron, +1 charge; highly reactive, especially with water (e.g., sodium, potassium).

• Alkaline Earth Metals: 2 valence electrons, +2 charge; reactive but less so than alkali metals (e.g., magnesium, calcium).

• Halogens: 7 valence electrons; form -1 ions and are diatomic in nature (e.g., fluorine, chlorine); highly reactive.

• Noble Gases: 8 valence electrons (full outer shell); generally inert and non-reactive (e.g., helium, neon).

Lewis Structures

• Drawing Method: Depict valence electrons as dots around element symbols; used to visualize how atoms bond and share electrons.

Significant Figures

• Rules: Important for precision in calculations; includes identifying significant digits, dealing with leading zeros, and rounding based on the precision of the measuring tool.

This guide provides an expanded overview of each section to aid in studying and understanding the fundamental concepts in chemistry.