Basic Concepts of Chemistry

Matter: Anything that has mass and occupies space; exists in three states: solid, liquid, gas.
Elements: Pure substances that cannot be broken down; defined by atomic number (number of protons).
Compounds: Substances made of two or more different elements chemically bonded together.

Atoms: Basic units of matter consisting of protons, neutrons, and electrons.
- Protons: Positively charged particles in the nucleus.
- Neutrons: Neutral particles in the nucleus.
- Electrons: Negatively charged particles orbiting the nucleus.
Isotopes: Atoms of the same element with different numbers of neutrons.

Ionic Bonds: Formed by the transfer of electrons from one atom to another, resulting in attraction between charged ions.
Covalent Bonds: Formed by the sharing of electrons between atoms.
Metallic Bonds: Involve a 'sea' of shared electrons among a lattice of metal atoms.

Reactants: Substances that undergo change in a chemical reaction.
Products: New substances formed as a result of a chemical reaction.
Types of Reactions:
- Synthesis: Two or more substances combine to form a new compound.
- Decomposition: A single compound breaks down into two or more simpler substances.
- Single Replacement: One element replaces another in a compound.
- Double Replacement: Exchange of ions between two compounds.
- Combustion: Reaction of a substance with oxygen, producing heat and light.

Mole: Quantity of substance containing 6.022 x 10²³ entities (Avogadro's number).
Molar Mass: Mass of one mole of a substance (g/mol).

Solid: Fixed shape and volume; particles are closely packed.
Liquid: Fixed volume but takes the shape of its container; particles are close but can move past one another.
Gas: No fixed shape or volume; particles are far apart and move freely.

Acids: Substances that donate protons (H⁺ ions); have a pH less than 7.
Bases: Substances that accept protons or donate hydroxide ions (OH⁻); have a pH greater than 7.
pH Scale: Measures acidity or basicity, ranging from 0 (acidic) to 14 (basic).

Groups: Vertical columns indicating elements with similar properties.
Periods: Horizontal rows indicating elements with increasing atomic numbers.
Metals, Nonmetals, Metalloids: Classification based on physical and chemical properties.

Hydrocarbons: Compounds composed solely of hydrogen and carbon.
Functional Groups: Specific groups of atoms that impart certain properties (e.g., -OH for alcohols, -COOH for carboxylic acids).
Isomerism: Compounds with the same molecular formula but different structures or arrangements.

Titration: Technique to determine the concentration of a solution.
Chromatography: Method for separating mixtures.
Spectroscopy: Analyzing materials based on their interaction with electromagnetic radiation.

Matter exists in three states: solid, liquid, and gas, characterized by having mass and occupying space.
Elements are pure substances defined by their atomic numbers, which correspond to the number of protons.
Compounds consist of two or more different elements chemically bonded together.

Atoms are the fundamental units of matter made up of protons, neutrons, and electrons.
Protons have a positive charge and are found in the nucleus of an atom.
Neutrons are uncharged particles also located in the nucleus.
Electrons, negatively charged, orbit around the nucleus.
Isotopes are variations of the same element that differ in neutron count.

Ionic bonds occur through electron transfer between atoms, leading to the formation of charged ions that attract each other.
Covalent bonds involve the sharing of electrons between atoms to achieve stability.
Metallic bonds consist of a delocalized 'sea' of electrons shared among metal atoms, facilitating conductivity.

Reactants are the initial substances that undergo transformation during a chemical reaction.
Products are the resulting substances formed after the reaction takes place.
Types of chemical reactions include:
- Synthesis: Combination of multiple substances to create one compound.
- Decomposition: Breakdown of a compound into simpler substances.
- Single Replacement: One element replaces another in a compound.
- Double Replacement: Ions are exchanged between two different compounds.
- Combustion: A substance reacts with oxygen, producing heat and light.

A mole represents a quantity of substance equating to 6.022 x 10²³ entities, known as Avogadro's number.
Molar mass refers to the mass of one mole of a substance, expressed in grams per mole (g/mol).

Solids have a definite shape and volume; particles are tightly packed and vibrate minimally.
Liquids maintain a constant volume but adapt their shape according to the container; particles are closely positioned yet mobile.
Gases lack a fixed shape or volume; particles are widely spaced and move freely.

Acids donate protons (H⁺ ions) and typically have a pH less than 7, indicating acidity.
Bases accept protons or donate hydroxide ions (OH⁻) and usually have a pH greater than 7, indicating basicity.
The pH scale ranges from 0 to 14, measuring the acidity or basicity of a solution.

Endothermic reactions absorb heat from their surroundings, leading to a temperature drop.
Exothermic reactions release heat, increasing the temperature of the surroundings.
Enthalpy (ΔH) indicates the heat content of a system and changes as a reaction progresses.

Groups are vertical columns grouping elements with similar chemical properties.
Periods are horizontal rows which show elements listed by increasing atomic number.
Elements are categorized as metals, nonmetals, or metalloids based on their physical and chemical characteristics.

Hydrocarbons are organic compounds made exclusively of carbon and hydrogen atoms.
Functional groups are specific atom groupings that confer distinct properties, such as -OH in alcohols and -COOH in carboxylic acids.
Isomerism occurs in compounds sharing the same molecular formula but possessing different structural configurations or arrangements.

Titration determines the concentration of a solution through precise addition of a reactant.
Chromatography separates components in a mixture based on their movement through a medium.
Spectroscopy analyzes materials based on their interaction with electromagnetic radiation, revealing structural and compositional information.