Basic Concepts of Chemistry

Atoms: The basic unit of matter, consisting of protons, neutrons, and electrons.
Molecules: Two or more atoms bonded together.
Elements: Pure substances made of one type of atom, listed in the periodic table.
Compounds: Substances formed when two or more different atoms chemically bond.

Solid: Definite shape and volume; particles tightly packed.
Liquid: Definite volume but takes the shape of the container; particles are close but can move.
Gas: No definite shape or volume; particles are far apart and move freely.
Plasma: Ionized gas with free electrons; found in stars and lightning.

Ionic Bonds: Formed by the transfer of electrons from one atom to another, resulting in charged ions.
Covalent Bonds: Involves the sharing of electron pairs between atoms.
Metallic Bonds: Occurs between metal atoms, involving a 'sea' of delocalized electrons.

Reactants: Substances that undergo a chemical change.
Products: Substances formed as a result of a chemical reaction.
Types of Reactions:
- Synthesis: Two or more reactants combine to form a product.
- Decomposition: A single compound breaks down into two or more simpler substances.
- Single Replacement: An element replaces another in a compound.
- Double Replacement: Exchange of ions between two compounds.

Mole: A quantity that represents 6.022 x 10²³ particles (Avogadro's number).
Molar Mass: The mass of one mole of a substance, usually expressed in grams/mole.
Balancing Equations: Ensures the same number of each type of atom on both sides of a chemical equation.

Acids: Substances that donate protons (H⁺ ions); they have a pH less than 7.
Bases: Substances that accept protons; they have a pH greater than 7.
pH Scale: Ranges from 0 to 14, measuring the acidity or basicity of a solution.

Exothermic Reactions: Release heat, temperature increases.
Endothermic Reactions: Absorb heat, temperature decreases.
Enthalpy (ΔH): The total heat content in a system; changes during reactions.

Personal Protective Equipment (PPE): Goggles, gloves, lab coats.
Proper Labeling: All chemicals must be clearly labeled with contents and hazards.
Emergency Procedures: Know locations of safety showers, eyewash stations, and fire extinguishers.

Atomic Radius: Increases down a group; decreases across a period.
Ionization Energy: Energy required to remove an electron; increases across a period; decreases down a group.
Electronegativity: Ability of an atom to attract electrons; increases across a period; decreases down a group.

These notes encompass essential concepts in chemistry, offering a structured overview suitable for study and reference.

Atoms are the foundational units of matter composed of protons, neutrons, and electrons.
Molecules form when two or more atoms bond together.
Elements are pure substances consisting of a single type of atom and are organized on the periodic table.
Compounds are formed when two or more different types of atoms chemically bond.

Solids have a definite shape and volume due to their tightly packed particles.
Liquids have a definite volume but take the shape of their container because their particles are close together but can move.
Gases lack a definite shape or volume; particles are far apart and move freely.
Plasma is an ionized gas with free electrons, commonly found in stars and lightning.

Ionic bonds occur when electrons are transferred from one atom to another, resulting in charged ions.
Covalent bonds involve the sharing of electron pairs between atoms.
Metallic bonds occur between metal atoms, featuring a 'sea' of delocalized electrons.

Reactants are substances that undergo a chemical change.
Products are substances created as a result of a chemical reaction.
Types of Reactions:
- Synthesis involves two or more reactants combining to form a product.
- Decomposition is the breakdown of a single compound into simpler substances.
- Single Replacement occurs when one element replaces another in a compound.
- Double Replacement involves the exchange of ions between two compounds.

Mole represents 6.022 x 10²³ particles (Avogadro's number), a fundamental unit of measurement in chemistry.
Molar mass is the mass of one mole of a substance, typically expressed in grams/mole.
Balancing equations ensures the same number of each type of atom appears on both sides of a chemical equation.

Acids are substances that donate protons (H⁺ ions), resulting in a pH less than 7.
Bases are substances that accept protons, resulting in a pH greater than 7.
pH scale ranges from 0 to 14, measuring the acidity or basicity of a solution.

Exothermic reactions release heat, causing a temperature increase.
Endothermic reactions absorb heat, leading to a temperature decrease.
Enthalpy (ΔH) represents the total heat content in a system, which can change during reactions.

Personal Protective Equipment (PPE) includes goggles, gloves, and lab coats.
Proper labeling is crucial to prevent accidents, with chemicals clearly labeled with contents and hazards.
Emergency Procedures require knowledge of the location of safety showers, eyewash stations, and fire extinguishers.

Atomic radius increases down a group and decreases across a period.
Ionization energy represents the energy needed to remove an electron; it increases across a period and decreases down a group.
Electronegativity reflects an atom's ability to attract electrons; it increases across a period and decreases down a group.

Solvent is the substance that dissolves the solute.
Solute is the substance being dissolved.
Concentration quantifies the amount of solute present in a given volume of solution.