Chemistry Overview and Key Concepts

Chemistry is the study of matter, involving its composition, structure, and changes, along with the energy involved in these changes.
Matter is defined as anything that occupies space and possesses mass.

Element: The simplest form of matter consisting of one type of atom.
Compound: A substance formed by two or more elements chemically combined in a definite ratio.
Mixture: A combination of two or more substances not chemically united.

Plasma: The colorless fluid in blood that transports cells and nutrients.
Serum: The yellowish liquid that separates from blood upon coagulation, rich in proteins and used for immunity and diagnostics.

Based on particle nature:
- Homogenous Mixture: Uniform composition throughout.
- Heterogenous Mixture: Composition varies in different parts.
Based on particle size:
- Solution: Uniform mixture (solute dissolved in solvent).
- Suspension: Coarse mixture of insoluble solid in liquid.
- Colloid: Intermediate state where particles are small but not fully dissolved.

Decantation: Based on density differences.
Distillation: Separation by evaporation and condensation.
Evaporation: Removal of liquid to isolate solids.
Magnetic Separation: Using magnets to separate magnetic materials.
Filtration: Separating solids from liquids using a barrier.
Sorting: Manual separation by observation.
Centrifugation: Utilizing centrifugal force for separation.
Fractional Crystallization: Crystallizing components at different temperatures.
Chromatography: Separation based on differences in solvent affinity.

Intrinsic/Intensive Properties: Independent of mass (e.g., density, melting point).
Extrinsic/Extensive Properties: Dependent on mass (e.g., weight, volume).

Gas evolution, precipitate formation, light emission, heat absorption or generation, and electrical generation.

Changes within the nucleus involving:
- Nuclear Fission: Splitting of heavy atomic nuclei.
- Nuclear Fusion: Combining of light atomic nuclei.

Democritus: Proposed matter consists of indivisible particles, naming them "atomos."
John Dalton: Introduced the "Billiard Ball Model"; outlined atomic theory regarding element similarities and combinations.
J.J. Thompson: Proposed "Raisin Bread" model; discovered electrons.
Ernest Rutherford: Identified the proton; suggested atoms are mostly empty space via the Gold Foil Experiment.
Niels Bohr: Created the planetary model of the atom.
Erwin Schrödinger: Developed the quantum mechanical model; introduced the concept of electron clouds.
James Chadwick: Discovered the neutron.

Allotropes: Different structural forms of the same element.
Examples include diamond and graphite for carbon and three forms of oxygen: nascent (O), molecular (O2), and ozone (O3).

Pauli’s Exclusion Principle: No two electrons can occupy the same quantum state; each orbital holds a maximum of 2 electrons.
Heisenberg Uncertainty Principle (incomplete context provided).

Law of Conservation of Mass: Mass remains constant in a closed system during a reaction.
Law of Definite Proportions: Compounds consist of elements in specific mass ratios.
Law of Multiple Proportions: Elements combine in ratios of small whole numbers to form different compounds.