1. Distinguishing Properties of Solids, Liquids, and Gases
o Solids:
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Liquids:
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Definite shape and volume.
Strong intermolecular forces.
Particles closely packed in a regular arrangement.
Definite volume but no fixed shape (takes the shape of the
container).
Moderate intermolecular forces.
Particles close together but not as ordered as solids.
Gases:
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No definite shape or volume (fills the entire container).
Weak intermolecular forces.
Particles move randomly and are widely spaced.
2. Structures of Solids, Liquids, and Gases
o Solids:
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Liquids:
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Particles are tightly packed in a regular lattice.
Vibrational motion around fixed positions.
Particles are close together but not in a fixed arrangement.
Random translational and rotational motion.
Gases:
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Particles are widely spaced and move freely.
Random translational motion.
3. Changes of State (Melting, Boiling, Evaporating, Freezing, and Condensing)
o Melting (Solid to Liquid):
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Heat energy breaks intermolecular bonds.
Particles gain kinetic energy and move more freely.
Boiling (Liquid to Gas):
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Heat energy overcomes intermolecular forces.
Particles escape the liquid phase.
o
Evaporating (Liquid to Gas at the Surface):
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Freezing (Liquid to Solid):
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Only surface particles gain enough energy to escape.
Heat energy is removed, and particles slow down.
Interparticle forces form a solid structure.
o
Condensing (Gas to Liquid):
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Heat energy is removed, and gas particles slow down.
Interparticle forces bring them closer together.
4. Heating and Cooling Curves
o Heating Curve:
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Temperature increases steadily during heating.
Plateaus at phase transitions (melting, boiling).
Cooling Curve:
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Temperature decreases steadily during cooling.
Plateaus at phase transitions (freezing, condensing).
5. Effects of Temperature and Pressure on Gas Volume
o Temperature (Charles’s Law):
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As temperature increases, gas volume increases (at constant
pressure).
Pressure (Boyle’s Law):
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As pressure increases, gas volume decreases (at constant
temperature).
6. Diffusion (Kinetic Particle Theory)
o Definition:
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Spontaneous mixing of particles due to their random motion.
Factors Affecting Diffusion Rate:
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Temperature (higher temperature → faster diffusion).
Molecular mass (lighter molecules diffuse faster).
1. Elements, Compounds, and Mixtures
o Element:
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Consists of only one type of atom.
Cannot be broken down into simpler substances.
o
Compound:
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Contains two or more different elements chemically bonded.
Has a fixed ratio of atoms.
Mixture:
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Contains different substances physically mixed.
Components retain their individual properties.
2. Atomic Structure
o Nucleus:
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Central part of an atom.
Contains protons and neutrons.
Electrons:
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Surround the nucleus in energy levels (shells).
Negatively charged.
Very low mass compared to protons and neutrons.
3. Relative Charges and Masses
o Proton:
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Neutron:
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Charge: +1
Mass: Approximately 1 atomic mass unit (u)
Charge: 0 (neutral)
Mass: Approximately 1 u
Electron:
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Charge: -1
Mass: Negligible (approximately 1/1836 u)
4. Proton Number (Atomic Number)
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Number of protons in an atom’s nucleus.
Determines the element’s identity.
5. Mass Number (Nucleon Number)
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Total number of protons and neutrons in an atom’s nucleus.
Not necessarily a whole number due to isotopes.
6. Electronic Configuration
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Describes the arrangement of electrons in energy levels.
Example: Sodium (Na) with proton number 11:
 Electronic configuration: 2, 8, 1 (2 electrons in the first shell, 8
in the second, and 1 in the third).
7. Periodic Table
o Group VIII (Noble Gases):
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Full outer shell (8 electrons).
o
Groups I to VII:
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Periods:
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Outer shell electrons equal to the group number.
Number of occupied electron shells equals the period number.