CHM101 Test 1 Review: Matter, Elements, and Atomic Structure

Matter and Energy

Classification of Matter

Matter is anything that has mass and occupies space. It can be classified based on its composition and properties.

• Pure Substances: Consist of only one type of particle. Includes elements (e.g., Aluminum (Al), Oxygen (O)) and compounds (e.g., Water (H2O)).

• Mixtures: Combinations of two or more substances. Can be homogeneous (uniform composition, e.g., salt water) or heterogeneous (non-uniform, e.g., sand and iron filings).

Example: Air is a homogeneous mixture; salad is a heterogeneous mixture.

States of Matter

Matter exists in three primary states: solids, liquids, and gases, each with distinct physical and chemical properties.

• Solids: Definite shape and volume; particles are closely packed.

• Liquids: Definite volume but no definite shape; particles are less tightly packed than solids.

• Gases: No definite shape or volume; particles are far apart and move freely.

Physical Properties: Color, density, melting point, boiling point.

Chemical Properties: Ability to react, flammability, toxicity.

Physical vs. Chemical Changes

Changes in matter can be classified as physical or chemical.

• Physical Change: Alters form but not composition (e.g., melting ice).

• Chemical Change: Produces new substances (e.g., burning wood).

Changes of State

Matter transitions between states through various processes:

• Melting: Solid to liquid

• Freezing: Liquid to solid

• Boiling/Evaporation: Liquid to gas

• Condensation: Gas to liquid

• Sublimation: Solid to gas

• Deposition: Gas to solid

Specific Heat

Specific heat is the amount of heat required to raise the temperature of 1 gram of a substance by 1°C.

• Formula:

$q = m \cdot c \cdot \Delta T$

• q: Heat energy (Joules)

• m: Mass (grams)

• c: Specific heat (J/g°C)

• \Delta T: Change in temperature (°C)

Heating and Cooling Curves

Heating and cooling curves show how temperature changes as heat is added or removed.

• Plateaus: Represent phase changes (e.g., melting, boiling).

• Slopes: Represent temperature changes within a single phase.

Example: During boiling, temperature remains constant while liquid changes to gas.

Elements and the Periodic Table

Common Elements and Their Symbols

Students should know the names and chemical symbols of common elements. See the list provided in the review sheet.

• Example: Gold (Au), Iron (Fe), Chlorine (Cl)

Periodic Table Structure

The Periodic Table organizes elements by increasing atomic number and similar properties.

• Periods: Horizontal rows

• Groups: Vertical columns

• Metals: Left and center; shiny, conductive

• Nonmetals: Right; dull, poor conductors

• Metalloids: Border metals and nonmetals; intermediate properties

Characteristics of Groups and Element Types

• Groups: Elements in the same group have similar chemical properties.

• Metals: Malleable, ductile, good conductors

• Nonmetals: Brittle, poor conductors

• Metalloids: Semi-conductors, properties of both metals and nonmetals

Atomic Theory and Structure

Parts of an Atom

Atoms consist of three main subatomic particles:

• Protons: Positive charge, found in nucleus

• Neutrons: No charge, found in nucleus

• Electrons: Negative charge, found outside nucleus

Atomic Number, Mass Number, and Atomic Mass

• Atomic Number (Z): Number of protons in nucleus

• Mass Number (A): Number of protons plus neutrons

• Atomic Mass: Weighted average mass of isotopes

Example: Carbon-12 has 6 protons and 6 neutrons; mass number = 12.

Electron Configuration

Electron configuration describes the arrangement of electrons in an atom.

• Shells: Energy levels (n=1, n=2, etc.)

• Subshells: s, p, d, f types within shells

• Orbitals: Regions where electrons are likely found

Example: Sodium (Na): 1s2 2s2 2p6 3s1

Periodic Table Trends

Several properties change predictably across the Periodic Table:

• Atomic Size: Decreases across a period, increases down a group

• Ionization Energy: Increases across a period, decreases down a group

• Metallic Character: Decreases across a period, increases down a group

Table: Common Elements and Their Symbols

The following table lists common elements and their chemical symbols:

Element Name	Symbol
Aluminum	Al
Argon	Ar
Arsenic	As
Barium	Ba
Boron	B
Bromine	Br
Cadmium	Cd
Calcium	Ca
Carbon	C
Chlorine	Cl
Chromium	Cr
Cobalt	Co
Copper	Cu
Fluorine	F
Gold	Au
Helium	He
Hydrogen	H
Iodine	I
Iron	Fe
Lead	Pb
Lithium	Li
Magnesium	Mg
Manganese	Mn
Mercury	Hg
Neon	Ne
Nickel	Ni
Nitrogen	N
Oxygen	O
Phosphorous	P
Potassium	K
Rubidium	Rb
Sulfur	S
Silicon	Si
Selenium	Se
Tin	Sn
Uranium	U
Zinc	Zn

Additional info: Academic context was added to expand brief points into full explanations, including definitions, examples, and formulas. The table was recreated for clarity and completeness.