Comprehensive Chemistry Review: Matter, Atomic Theory, Bonding, and Gas Laws

Atomic theory - Thomson

Discovered electrons (cathode ray tube)

Atomic theory - Rutherford

Discovered nucleus (gold foil)

Examples of physical change

Tearing paper, dissolving sugar, melting, freezing, evaporating, breaking glass.

Chemical change

New substance formed

Extensive property

Depends on amount (mass, volume).

Intensive property

Does NOT depend on amount (density, color, boiling point).

Significant figures - leading zeros

Not significant

Significant figures - captive zeros

Significant

Significant figures - trailing zeros

Significant only if decimal is present

Multiplication/division with significant figures

Least number of significant figures

Addition/subtraction with significant figures rule

Use the least number of decimal places when adding or subtracting.

Scientific notation

Move decimal until 1 digit remains on the left.

Density formula

D = M/V

Atomic theory - Dalton

atoms are indivisible and are the smallest unit of matter.

Physical change

Identity stays the same

Examples of chemical change

Rusting, burning gas, respiration.

Atomic theory - Bohr

Electrons in energy levels

Atomic theory - modern model

Electron cloud

Protons

Equal atomic number

Neutrons

Mass number - protons

Electrons in a neutral atom

Equal to protons

Isotopes

Same protons, different neutrons

Ions

Electrons gained/lost

Paramagnetic

Unpaired electrons

Diamagnetic

All paired electrons

Atomic radius trend

Increases down and left

Ionization energy trend

Increases up and right

Electronegativity trend

Increases up and right

Highest electronegativity element

Fluorine (F)

Largest atomic radius element

Francium (Fr)

Ionic bonding

Metal + nonmetal, electrons transferred

Covalent bonding

Nonmetal + nonmetal, electrons shared

Metallic bonding

Metal + metal

Electronegativity difference for nonpolar covalent

<0.3

Electronegativity difference for polar covalent

0.3-1.7

Electronegativity difference for ionic

≥1.7

Linear molecular geometry

180°

Trigonal planar molecular geometry

120°

Tetrahedral molecular geometry

109.5°

Trigonal pyramidal molecular geometry

107°

Bent molecular geometry

104.5°

London dispersion forces

Weakest, present in all molecules

Dipole-dipole forces

Present in polar molecules

Hydrogen bonding

H bonded to N, O, or F (strongest)

Ionic compound naming

Metal + nonmetal, transition metals need Roman numerals

Covalent compound naming

Use prefixes (mono, di, tri...)

Balancing equations

Atoms on left = atoms on right

Synthesis reaction

A + B → AB

Decomposition reaction

AB → A + B

Single replacement reaction

A + BC → AC + B

Double replacement reaction

AB + CD → AD + CB

Combustion reaction

Hydrocarbon + O₂ → CO₂ + H₂O

Stoichiometry

Use mole ratios from balanced equations.

Gas law - Boyle's Law

P₁V₁ = P₂V₂

Gas law - Charles' Law

V₁/T₁ = V₂/T₂

Gas law - Gay-Lussac's Law

P₁/T₁ = P₂/T₂

Gas law - Combined Gas Law

P₁V₁/T₁ = P₂V₂/T₂

Gas law - Ideal Gas Law

PV = nRT

STP conditions

1 atm, 273 K, 22.4 L/mol

Heating curve - sloped lines

Kinetic energy increases

Heating curve - flat lines

Potential energy increases (phase change)

Melting point

Solid ↔ liquid

Boiling point

Liquid ↔ gas

Intermolecular forces overcome during

Melting & boiling

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