Basic Concepts of Chemistry

Atoms: Basic units of matter, consisting of protons, neutrons, and electrons.
Molecules: Two or more atoms bonded together; can be diatomic (e.g., O₂) or polyatomic (e.g., H₂O).
Elements: Pure substances made of only one type of atom, represented in the periodic table.
Compounds: Substances formed from two or more different elements that are chemically bonded.

Solid: Definite shape and volume, particles are closely packed.
Liquid: Definite volume but no definite shape, particles are close but can flow.
Gas: No definite shape or volume, particles are far apart and move freely.
Plasma: Ionized gas with free electrons, conducts electricity, found in stars.

Ionic Bonds: Formed when electrons are transferred from one atom to another, creating charged ions.
Covalent Bonds: Formed when two atoms share electrons.
Metallic Bonds: Occur between metal atoms; electrons are shared in a "sea" of electrons.

Reactants: Substances that undergo a chemical change.
Products: New substances formed as a result of a chemical reaction.
Types of Reactions:
- Synthesis: A + B → AB
- Decomposition: AB → A + B
- Single Replacement: A + BC → AC + B
- Double Replacement: AB + CD → AC + BD
- Combustion: Hydrocarbon + O₂ → CO₂ + H₂O

Groups/Families: Vertical columns with similar chemical properties (e.g., alkali metals, halogens).
Periods: Horizontal rows indicating energy levels of electrons.
Metals, Nonmetals, Metalloids: Classification of elements based on properties.

Acids: Substances that donate protons (H⁺) in solution, characterized by a sour taste.
Bases: Substances that accept protons or donate hydroxide ions (OH⁻), characterized by a bitter taste and slippery feel.
pH Scale: Measures acidity or alkalinity of a solution; ranges from 0 (acidic) to 14 (basic), with 7 being neutral.

Mole Concept: A mole is 6.022 x 10²³ particles (atoms, molecules, etc.).
Balancing Equations: Ensures the law of conservation of mass; number of atoms for each element must be the same on both sides of the equation.

Hydrocarbons: Compounds consisting solely of carbon and hydrogen; can be aliphatic (linear) or aromatic (ring).
Functional Groups: Specific groups of atoms in organic molecules that dictate their chemical properties (e.g., alcohols, carboxylic acids).

Solute: Substance dissolved in a solvent.
Solvent: Substance that dissolves the solute; commonly water.
Concentration: Measure of how much solute is dissolved in a given amount of solvent (e.g., molarity, percent by volume).

Personal Protective Equipment (PPE): Safety goggles, gloves, lab coats.
Chemical Hygiene: Proper handling, storage, and disposal of chemicals to minimize risks.
Emergency Procedures: Knowledge of procedures for chemical spills, fires, and injuries.

Atoms are the foundational building blocks of matter, composed of protons (positively charged), neutrons (neutral), and electrons (negatively charged).
Molecules consist of two or more atoms bonded together; examples include diatomic molecules like O₂ and polyatomic molecules like H₂O.
Elements are pure substances made of a single type of atom, each represented by unique symbols in the periodic table.
Compounds are substances formed through chemical bonds between different elements, showcasing distinct properties from the individual elements.

Solids maintain a definite shape and volume due to tightly packed particles that vibrate in place.
Liquids have a definite volume but take on the shape of their container, with particles closely spaced yet able to move past one another.
Gases lack both definite shape and volume, consisting of widely spaced particles that move freely.
Plasma, a high-energy state of matter where gas is ionized, contains free electrons and conducts electricity, occurring naturally in stars.

Ionic bonds are formed through the transfer of electrons from one atom to another, resulting in charged ions that attract each other.
Covalent bonds arise when two atoms share electrons, resulting in a stable molecule.
Metallic bonds involve a 'sea' of electrons shared among a lattice of metal atoms, allowing conductance and malleability.

Reactants are the starting substances that undergo transformation during a chemical reaction.
Products are the new substances created as a result of the chemical reaction.
Types of chemical reactions:
- Synthesis: Combines reactants to form a larger compound (A + B → AB).
- Decomposition: Breaks a compound into simpler products (AB → A + B).
- Single Replacement: One element replaces another in a compound (A + BC → AC + B).
- Double Replacement: Ions in two compounds exchange places (AB + CD → AC + BD).
- Combustion: Hydrocarbons react with oxygen to produce carbon dioxide and water (Hydrocarbon + O₂ → CO₂ + H₂O).

Groups (vertical columns) contain elements with similar properties, such as alkali metals or halogens.
Periods (horizontal rows) indicate the number of electron energy levels in the elements.
Elements are classified as metals, nonmetals, or metalloids based on their physical and chemical properties.

Acids produce protons (H⁺) in solution and are typically sour in taste.
Bases accept protons or provide hydroxide ions (OH⁻), described as having a bitter taste and slippery feel.
The pH scale measures the acidity or basicity of a solution, ranging from 0 (acidic) to 14 (basic), with 7 indicating neutrality.

A mole, quantified as 6.022 x 10²³ particles, serves as a bridge for converting between particles, moles, and grams in chemical equations.
Balancing equations is essential for adhering to the law of conservation of mass, ensuring equal numbers of atoms of each element on both sides of the equation.

Endothermic reactions absorb heat, causing the surroundings to cool.
Exothermic reactions release heat, resulting in an increase in temperature in the surroundings.
Enthalpy (ΔH) represents the total heat content of a system under constant pressure.

Hydrocarbons are organic compounds composed solely of carbon and hydrogen, categorized as aliphatic (straight-chain) or aromatic (ringed structures).
Functional groups are specific atom groupings in organic molecules that determine their reactivity and properties, such as alcohols and carboxylic acids.

A solute is the substance dissolved within a solvent, the substance doing the dissolving, commonly water.
Concentration quantifies the amount of solute dissolved in a specified volume of solvent, with common measures including molarity and percent by volume.

Personal Protective Equipment (PPE) includes essential safety gear such as goggles, gloves, and lab coats to protect from hazards.
Chemical hygiene involves safe handling, storage, and disposal practices to prevent accidents and exposure.
Familiarity with emergency procedures is crucial for effectively addressing chemical spills, fires, and injuries in the lab environment.