Basic Concepts in 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 the number of protons (atomic number).
Compounds: Substances formed from two or more elements chemically combined in fixed ratios.

Atoms: Basic units of matter, consisting of protons, neutrons, and electrons.
- Protons: Positively charged, found in the nucleus.
- Neutrons: Neutral charge, also in the nucleus.
- Electrons: Negatively charged, orbiting the nucleus in electron shells.
Isotopes: Variants of elements with the same number of protons but different numbers of neutrons.

Ionic Bonds: Formed when electrons are transferred from one atom to another; results in charged ions.
Covalent Bonds: Formed when atoms share electrons.
Metallic Bonds: Characterized by a 'sea of electrons' that allow for electrical conductivity and malleability.

Reactants: Substances consumed during a chemical reaction.
Products: Substances produced from a chemical reaction.
Types of Reactions:
- Synthesis: Combining reactants to form a compound.
- Decomposition: Breaking down a compound into simpler products.
- Single Replacement: One element replaces another in a compound.
- Double Replacement: Exchange of ions between two compounds.
- Combustion: Reaction with oxygen producing heat and light; often produces CO₂ and H₂O.

Groups/Families: Vertical columns, share similar chemical properties.
Periods: Horizontal rows, indicate energy levels of electrons.
Metals, Nonmetals, Metalloids: Distinct categories based on physical and chemical properties.

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

Solution: Homogeneous mixture of solute and solvent.
Solvent: Substance that dissolves a solute; usually present in greater amount.
Solute: Substance being dissolved; present in lesser amount.
Suspensions and Colloids: Types of heterogeneous mixtures with different properties.

Acids: Substances that donate protons (H⁺) in solutions; have a pH < 7.
Bases: Substances that accept protons or donate hydroxide ions (OH⁻); have a pH > 7.
pH Scale: Measures the acidity or basicity of a solution (0-14 scale).

Endothermic Reactions: Absorb heat from the surroundings.
Exothermic Reactions: Release heat to the surroundings.
Law of Conservation of Energy: Energy cannot be created or destroyed, only transformed.

Titration: Technique to determine concentration of a solution by reaction with a standard solution.
Filtration: Separates solids from liquids using a barrier.
Distillation: Separates mixtures based on differences in boiling points.

Hydrocarbons: Compounds made solely of carbon and hydrogen.
Functional Groups: Specific groups of atoms within molecules that determine chemical properties.
Isomerism: Compounds with the same formula but different structures or spatial arrangements.

Matter includes anything with mass and volume, typically classified into solid, liquid, and gas states.
Elements are pure substances, distinguished by their atomic number (number of protons) and cannot be decomposed chemically.
Compounds consist of two or more elements bonded in fixed ratios forming a new substance.

Atoms are the fundamental units of matter, composed of protons (positive charge), neutrons (neutral), and electrons (negative charge).
Protons and neutrons reside in the atom’s nucleus, while electrons occupy surrounding energy levels or electron shells.
Isotopes are variations of an element defined by equal protons but differing neutron counts.

Ionic bonds occur when electrons are transferred between atoms, resulting in oppositely charged ions.
Covalent bonds form through the sharing of electrons between atoms.
Metallic bonds feature delocalized electrons, facilitating electrical conductivity and malleability in metals.

Reactants are the initial substances involved in a chemical reaction; products are the new substances formed.
Types of chemical reactions include:
- Synthesis: formation of a compound from simpler substances.
- Decomposition: breakdown of a compound into simpler constituents.
- Single Replacement: one element substitutes for another in a compound.
- Double Replacement: ions are exchanged between two compounds.
- Combustion: reaction with oxygen, producing heat and light, typically forming CO₂ and H₂O.

Groups (vertical columns) represent elements with similar chemical behaviors, while periods (horizontal rows) indicate electron energy levels.
Elements are categorized as metals, nonmetals, or metalloids based on their properties.

Solids maintain a definite shape and volume due to tightly packed particles.
Liquids have a fixed volume but adapt to the shape of their container, with particles that can slide past one another.
Gases have neither a fixed shape nor volume; particles are dispersed and move freely.

A solution is a homogeneous mixture of solute and solvent where the solute is dissolved in the solvent.
The solvent is present in greater quantity, while the solute is in minor quantity.
Suspensions and colloids represent heterogeneous mixtures, differing in particle size and behavior.

Acids release protons (H⁺) when dissolved in water and exhibit a pH below 7.
Bases accept protons or release hydroxide ions (OH⁻), with a pH above 7.
The pH scale ranges from 0 to 14, assessing the acidity or alkalinity of solutions.

Endothermic reactions absorb heat energy from the surroundings.
Exothermic reactions release heat energy into the surroundings.
The Law of Conservation of Energy states that energy cannot be created or destroyed, only converted between forms.

Titration is used to determine the concentration of a solution by reacting it with a known standard.
Filtration separates solid particles from liquids via a barrier.
Distillation separates components of mixtures based on their boiling point differences.

Hydrocarbons are organic compounds consisting solely of carbon and hydrogen atoms.
Functional groups are specific atom arrangements within organic compounds that determine their chemical reactivity.
Isomerism describes compounds sharing the same molecular formula but differing in structural or spatial arrangements.