Basic Concepts of Chemistry

Matter: Anything that has mass and occupies space. Can exist in solid, liquid, and gas states.
Atoms: Basic units of matter, consisting of protons, neutrons, and electrons.
- Protons: Positively charged, found in nucleus.
- Neutrons: Neutral charge, also in nucleus.
- Electrons: Negatively charged, orbit the nucleus.
Elements: Pure substances made of only one type of atom. Defined by atomic number (number of protons).
Compounds: Substances formed when two or more elements chemically bond in fixed proportions.

Reactants and Products:
- 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 one product.
- Decomposition: A single compound breaks down into two or more products.
- Single Replacement: An element replaces another in a compound.
- Double Replacement: Exchange of ions between two compounds.
- Combustion: A substance reacts with oxygen, releasing energy.

Electron Configuration: Describes the distribution of electrons in an atom's orbitals.
- Follow the Aufbau principle, Pauli exclusion principle, and Hund’s rule.
Isotopes: Atoms of the same element with different numbers of neutrons and thus different atomic masses.

Ionic Bonds: Formed through the transfer of electrons from one atom to another, resulting in charged ions.
Covalent Bonds: Formed when two atoms share electrons.
Metallic Bonds: Involve a 'sea of electrons' shared among a lattice of metal atoms.

Organization: Elements arranged by increasing atomic number, grouped by similar properties.
Periods: Horizontal rows; indicate energy levels of electrons.
Groups: Vertical columns; elements share similar chemical properties.

Acids: Substances that donate protons (H+) in a solution; pH < 7.
Bases: Substances that accept protons; pH > 7.
pH Scale: Measures acidity or basicity; ranges from 0 (acidic) to 14 (basic), with 7 being neutral.

Mole Concept: A mole represents 6.022 × 10²³ particles (Avogadro's number).
Balancing Chemical Equations: Ensures conservation of mass by having equal numbers of each type of atom on both sides of the equation.

Enthalpy (ΔH): The heat content of a system; positive for endothermic reactions and negative for exothermic reactions.
Gibbs Free Energy (ΔG): Determines spontaneity of a reaction; ΔG < 0 indicates a spontaneous reaction.

Reaction Rate: Speed at which reactants convert to products, influenced by concentration, temperature, and catalysts.
Chemical Equilibrium: State where the rates of the forward and reverse reactions are equal, leading to constant concentrations of reactants and products.

Hydrocarbons: Organic compounds consisting entirely of carbon and hydrogen.
- Alkanes: Saturated hydrocarbons (single bonds).
- Alkenes: Unsaturated hydrocarbons (at least one double bond).
- Alkynes: Unsaturated hydrocarbons (at least one triple bond).
Functional Groups: Specific groups of atoms within molecules that determine the chemical reactivity and properties (e.g., hydroxyl, carbonyl, carboxyl groups).

Matter encompasses everything with mass and volume. It exists in three states: solid, liquid, and gas.
Atoms are the smallest unit of matter, consisting of protons, neutrons, and electrons.
Protons, located in the nucleus, carry a positive charge.
Neutrons, also found in the nucleus, are neutral.
Electrons, carrying a negative charge, orbit the nucleus in electron shells.
Elements are pure substances made solely of one type of atom, defined by their atomic number, which indicates the number of protons.
Compounds are formed when two or more elements chemically combine in fixed ratios.

Reactants are the substances that undergo chemical change in a reaction.
Products are the substances formed as a result of the reaction.
Synthesis reactions involve the combination of two or more reactants to create a single product.
Decomposition reactions are the opposite of synthesis, where a single compound breaks down into two or more products.
Single replacement reactions involve an element replacing another in a compound.
Double replacement reactions involve the exchange of ions between two compounds.
Combustion reactions involve the reaction of a substance with oxygen, releasing energy.

Electron configuration explains the distribution of electrons within an atom's orbitals, governed by the Aufbau principle, the Pauli exclusion principle, and Hund's rule.
Isotopes are atoms of the same element with differing numbers of neutrons, resulting in different atomic masses.

Ionic bonds form when electrons are transferred between atoms, creating charged ions that attract each other electrostatically.
Covalent bonds form when two atoms share electrons, resulting in a stable molecule.
Metallic bonds involve a sea of electrons shared amongst a lattice of metal atoms, accounting for their unique properties.

The periodic table organizes elements by increasing atomic number, grouping elements with similar properties.
Periods are horizontal rows corresponding to the electron energy levels.
Groups are vertical columns, where elements share similar chemical properties due to similar electron configurations in their outer shells.

Acids are substances that donate protons (H+) in solution, resulting in a pH less than 7, making them acidic.
Bases are substances that accept protons (H+) in solution, resulting in a pH greater than 7, making them basic.
The pH scale measures acidity or basicity ranging from 0 (most acidic) to 14 (most basic), with 7 being neutral.

The mole concept defines a mole as 6.022 × 10²³ particles, known as Avogadro's number.
Balancing chemical equations ensures that the number of each type of atom on both sides of the equation is equal, satisfying the law of conservation of mass.

Enthalpy (ΔH) represents the heat content of a system. A positive ΔH indicates an endothermic reaction that absorbs heat, while a negative ΔH indicates an exothermic reaction that releases heat.
Gibbs free energy (ΔG) predicts the spontaneity of a reaction. A negative ΔG signifies a spontaneous reaction.

Reaction rate describes the speed at which a reaction proceeds. It is influenced by factors like concentration, temperature, and the presence of catalysts.
Chemical equilibrium is attained when the rates of the forward and reverse reactions are equal, resulting in constant concentrations of reactants and products.

Hydrocarbons are organic compounds solely composed of carbon and hydrogen.
Alkanes are saturated hydrocarbons with single bonds between carbon atoms.
Alkenes are unsaturated hydrocarbons containing at least one double bond between carbon atoms.
Alkynes are unsaturated hydrocarbons with at least one triple bond between carbon atoms.
Functional groups are specific groups of atoms within molecules that determine their unique chemical reactivity and properties (e.g., hydroxyl, carbonyl, carboxyl groups).