Basic Chemistry Concepts

Atoms: Basic units of matter, consisting of protons, neutrons, and electrons.
Molecules: Two or more atoms bonded together.
Elements: Pure substances that cannot be broken down; identified by atomic number.
Compounds: Substances formed from two or more different elements chemically bonded.

Solid: Definite shape and volume; particles closely packed.
Liquid: Definite volume but takes the shape of the container; particles less tightly packed.
Gas: No definite shape or volume; particles are far apart and move freely.

Ionic Bonds: Formed by the transfer of electrons from one atom to another, creating charged ions.
Covalent Bonds: Involve the sharing of electron pairs between atoms.
Metallic Bonds: Involve a 'sea of electrons' allowing for conductivity and malleability.

Reactants and Products: Substances that undergo change (reactants) and those that are produced (products).
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: A unit used to measure the amount of substance, equivalent to Avogadro's number (6.022 x 10²³ particles).
Molar Mass: Mass of one mole of a substance, calculated from the atomic masses of its elements.

Solvent: Substance in which solute dissolves (usually liquid).
Solute: Substance that is dissolved in a solvent.
Concentration: Amount of solute in a given volume of solvent (e.g., molarity = moles/L).

Acids: Substances that produce hydrogen ions (H⁺) in solution; have a pH < 7.
Bases: Substances that produce hydroxide ions (OH⁻); have a pH > 7.
pH Scale: Measures acidity or basicity; ranges from 0 to 14 with 7 being neutral.

Endothermic Reaction: Absorbs heat; energy is needed for the reaction to occur.
Exothermic Reaction: Releases heat; energy is released during the reaction.

Groups/Families: Vertical columns that share similar properties.
Periods: Horizontal rows indicating energy levels.
Metals, Nonmetals, Metalloids: Classification based on properties such as conductivity and malleability.

Catalyst: Substance that speeds up a chemical reaction without being consumed.
Entropy: Measure of disorder or randomness in a system.
Equilibrium: State where the forward and reverse reactions occur at the same rate.

Atoms are the smallest units of matter and consist of protons, neutrons, and electrons.
Molecules are formed when two or more atoms bond together.
Elements are pure substances that cannot be broken down into simpler substances and are identified by their atomic number.
Compounds are formed when two or more different elements combine chemically.

Solids have a definite shape and volume, with particles tightly packed together.
Liquids have a definite volume but take the shape of their container, with particles less tightly packed than solids.
Gases have no definite shape or volume, with widely spaced particles moving freely.

Ionic Bonds form when electrons are transferred between atoms, creating charged ions that are attracted to each other.
Covalent Bonds form when atoms share pairs of electrons.
Metallic Bonds involve a 'sea of electrons' that allows for good conductivity and malleability.

Reactants are the substances that undergo change in a chemical reaction.
Products are the substances that are formed in a chemical reaction.
Synthesis reactions combine reactants to form a single product (A + B → AB).
Decomposition reactions break down a reactant into multiple products (AB → A + B).
Single Replacement reactions involve one element replacing another in a compound (A + BC → AC + B).
Double Replacement reactions involve the exchange of ions between two compounds (AB + CD → AD + CB).
Combustion reactions involve the rapid reaction of a substance with oxygen, producing heat and light (Hydrocarbon + O₂ → CO₂ + H₂O).

Mole (mol) is a unit of measurement for the amount of substance, equivalent to Avogadro's number (6.022 x 10²³ particles).
Molar Mass is the mass of one mole of a substance, calculated from the atomic masses of its constituent elements.

Solvent is the substance in which a solute dissolves, typically a liquid.
Solute is the substance that dissolves in a solvent.
Concentration refers to the amount of solute present in a given volume of solvent. Molarity is a common unit of concentration, expressed as moles of solute per liter of solution (mol/L).

Acids are substances that produce hydrogen ions (H⁺) in solution, resulting in a pH less than 7.
Bases are substances that produce hydroxide ions (OH⁻) in solution, resulting in a pH greater than 7.
pH Scale measures the acidity or basicity of a solution, ranging from 0 to 14 with 7 being neutral.

Endothermic reactions absorb heat from the surroundings, making the surroundings colder.
Exothermic reactions release heat to the surroundings, making the surroundings hotter.

Groups/Families are vertical columns in the periodic table, containing elements with similar properties.
Periods are horizontal rows in the periodic table, indicating the energy levels of the elements.
Metals are typically shiny, malleable, and good conductors of heat and electricity.
Nonmetals generally lack the properties of metals, often being poor conductors of heat and electricity.
Metalloids exhibit properties of both metals and nonmetals.

Always wear safety goggles and gloves when working with chemicals.
Familiarize yourself with the location of safety equipment, such as eyewash stations and fire extinguishers.
Dispose of chemicals properly according to safety protocols.

Catalyst is a substance that speeds up a chemical reaction without being consumed in the process.
Entropy is a measure of the disorder or randomness in a system.
Equilibrium is a state where the forward and reverse reactions occur at the same rate, resulting in no net change in concentrations of reactants and products.