General Chemistry

Atoms

The fundamental building blocks of matter.

Core

Contains protons and neutrons.

Electrons

Orbit the core of an atom.

Elements

Different types of atoms based on their number of protons.

Valence Electrons

Electrons in the outermost shell of an atom.

Periodic Table

A table organizing elements based on their properties.

Groups

Columns in the periodic table representing elements with the same number of valence electrons.

Periods

Rows in the periodic table representing elements with the same number of electron shells.

Isotopes

Atoms of the same element with different numbers of neutrons.

Ions

Charged atoms.

Cations

Positive ions.

Anions

Negative ions.

Symbol

Abbreviation for an element in the periodic table.

Atomic Number

Number of protons in an atom.

Atomic Mass

Average mass of atoms of an element.

Metals

Elements located on the left side of the periodic table.

Non-metals

Elements located on the right side of the periodic table.

Semimetals

Elements located between metals and non-metals.

Molecules

Two or more atoms bonded together.

Compounds

Molecules composed of at least two different elements.

Molecular Formula

Shows the number of each atom in a molecule.

Isomers

Molecules with the same molecular formula but different structures.

Covalent Bonds

Sharing of electrons between atoms.

Electronegativity

The ability of an atom to attract electrons.

Ionic Bonds

Transfer of electrons between atoms, forming ions.

Metallic Bonds

Sharing of electrons between metal atoms.

Intermolecular Forces

Forces between molecules.

Hydrogen Bonds

Strong dipole-dipole interactions.

Van der Waals Forces

Weak temporary attractions between molecules.

Solid

State of matter with a fixed shape and volume.

Liquid

State of matter with a fixed volume but variable shape.

Gas

State of matter with no fixed shape or volume.

Plasma

Highly ionized gas.

Temperature

Average kinetic energy of particles in a substance.

Entropy

Measure of disorder in a system.

Synthesis

A type of chemical reaction where substances combine.

Decomposition

A type of chemical reaction where substances break down.

Stoichiometry

The quantitative relationship between reactants and products in a chemical reaction.

Balancing Equations

Ensuring the same number of atoms of each element on both sides of a chemical equation.

The Mole

A unit of measurement for the amount of a substance.

Physical Change

Alters the appearance without changing the substance.

Chemical Change

Creates new substances through a reaction.

Activation Energy

The energy required to start a chemical reaction.

Catalysts

Substances that speed up reactions without being consumed.

Enthalpy

The heat content of a system.

Exothermic

A reaction that releases heat.

Endothermic

A reaction that absorbs heat.

Gibbs Free Energy

Determines the spontaneity of a reaction.

Chemical Equilibrium

A state where the rates of the forward and reverse reactions are equal.

Brønsted-Lowry Theory

Acids donate protons, bases accept protons.

pH

Measure of acidity or basicity of a solution.

Neutralization Reactions

Reactions between acids and bases that produce water and a salt.

Redox Reactions

Reactions involving the transfer of electrons.

Oxidation Numbers

Indicate the degree of oxidation or reduction of an atom.

Quantum Numbers

Describe the properties of electrons in an atom.

n

Principal quantum number (shell).

l

Azimuthal quantum number (subshell).

ml

Magnetic quantum number (orbital).

ms

Spin quantum number.

Electron Configuration

The arrangement of electrons in an atom's orbitals.

Aufbau Principle

The order in which orbitals are filled.