Fundamental Chemistry Concepts

Matter: Anything that has mass and occupies space. Divided into:
- Elements: Pure substances that cannot be broken down (e.g., hydrogen, oxygen).
- Compounds: Substances formed from two or more elements chemically combined (e.g., H2O).
Atoms: The basic unit of matter, composed of:
- Protons: Positive charge, found in the nucleus.
- Neutrons: No charge, also in the nucleus.
- Electrons: Negative charge, orbiting the nucleus.
Atomic Number: Number of protons in an atom; determines the element.
Mass Number: Total number of protons and neutrons in an atom.

Groups: Vertical columns in the periodic table; elements in the same group have similar properties.
Periods: Horizontal rows; properties change progressively across a period.
Metals, Nonmetals, and Metalloids:
- Metals: Good conductors of heat/electricity, malleable, ductile.
- Nonmetals: Poor conductors, diverse states at room temperature.
- Metalloids: Properties intermediate between metals and nonmetals.

Ionic Bonds: Formed when electrons are transferred from one atom to another, resulting in charged ions.
Covalent Bonds: Formed when atoms share electrons; can be polar (unequal sharing) or nonpolar (equal sharing).
Metallic Bonds: Occur between metal atoms, allowing for free movement of electrons.

Reactants: Substances going into a reaction.
Products: Substances produced in a reaction.
Types of Reactions:
- Synthesis: A + B → AB
- Decomposition: AB → A + B
- Single Replacement: A + BC → AC + B
- Double Replacement: AB + CD → AD + CB
- Combustion: Hydrocarbon + O2 → CO2 + H2O

Mole: Unit for measuring the amount of substance; 1 mole = 6.022 x 10^23 particles.
Molar Mass: Mass of one mole of a substance (g/mol).
Conversions:
- From grams to moles: moles = grams/molar mass.
- From moles to molecules: molecules = moles x Avogadro's number.

Acids: Substances that donate protons (H+) in solution; characterized by sour taste and pH < 7.
Bases: Substances that accept protons or donate hydroxide ions (OH-) in solution; characterized by bitter taste and pH > 7.
pH Scale: Measures acidity/alkalinity; scale ranges from 0 (acidic) to 14 (basic) with 7 being neutral.

Endothermic Reactions: Absorb heat energy from surroundings.
Exothermic Reactions: Release heat energy to surroundings.
Law of Conservation of Mass: Matter is not created or destroyed in a chemical reaction.

Solvent: The substance that dissolves the solute (e.g., water).
Solute: The substance that is dissolved (e.g., salt).
Concentration: Amount of solute per unit volume of solution (often expressed in molarity, M).

This summary covers essential topics in fundamental chemistry, providing a quick reference for basic principles and concepts.

Matter is anything that has mass and takes up space.
Elements are pure substances that cannot be broken down into simpler substances. Examples include hydrogen and oxygen.
Compounds are formed when two or more elements chemically combine. Water (H₂O) is a common example.
Atoms are the basic building blocks of matter. They are composed of protons, neutrons, and electrons.
- Protons are positively charged particles found in the nucleus of an atom.
- Neutrons are particles with no charge, also found in the nucleus.
- Electrons are negatively charged particles that orbit the nucleus.
Atomic Number: This number represents the number of protons in an atom's nucleus. It determines the element.
Mass Number: This represents the total number of protons and neutrons in an atom.

Groups are vertical columns in the Periodic Table. Elements within the same group share similar properties.
Periods are horizontal rows in the Periodic Table. The properties of elements change as you move across a period.
Metals, nonmetals, and metalloids are three categories of elements:
- Metals are good conductors of heat and electricity, malleable (can be hammered into shapes), and ductile (can be drawn into wires).
- Nonmetals are generally poor conductors of heat and electricity. They exist in various states at room temperature.
- Metalloids exhibit properties that are intermediate between those of metals and nonmetals.

Ionic bonds are formed when one atom transfers electrons to another atom. This results in the formation of charged ions, which are attracted to each other.
Covalent bonds are formed when atoms share electrons. This can be either polar, where electrons are shared unequally, or nonpolar, where electrons are shared equally.
Metallic bonds occur between metal atoms. They allow electrons to move freely, contributing to their conductibility.

Mole represents the amount of a substance. One mole contains 6.022 x 10²³ particles (Avogadro's number).
Molar mass is the mass of one mole of a substance. It is expressed in grams per mole (g/mol).
Conversions:
- Grams to moles: moles = grams / molar mass
- Moles to molecules: molecules = moles x Avogadro's number

Acids are substances that donate protons (H⁺) in solution. They are characterized by a sour taste and a pH less than 7.
Bases are substances that accept protons or donate hydroxide ions (OH⁻) in solution. They are characterized by a bitter taste and a pH greater than 7.
pH Scale: Measures the acidity or alkalinity of a solution. It ranges from 0 (acidic) to 14 (basic), with 7 being neutral.

Endothermic reactions absorb heat energy from their surroundings.
Exothermic reactions release heat energy to their surroundings.
Law of Conservation of Mass: Matter cannot be created or destroyed in a chemical reaction.

Solvent: The substance that dissolves the solute (e.g., water).
Solute: The substance that is dissolved (e.g., salt).
Concentration: The amount of solute per unit volume of solution. This is frequently expressed in molarity (M).