"A particle that consists of a nucleus of protons and neutrons surrounded by an electromagnetically-bound cloud of electrons."
This subfield studies the structure and properties of atoms and molecules.
Atomic Structure: This includes the study of the arrangement of electrons and protons in an atom, the quantum mechanical model of an atom, the Bohr model, and the atomic spectrum.
Properties of Electrons: This includes the study of the wave-particle duality of electrons, Heisenberg's uncertainty principle, and the electron configuration of an atom.
Chemical Bonding: This includes the study of how atoms form chemical bonds with each other, the types of chemical bonds (ionic, covalent, and metallic), electronegativity, and polarity.
Molecular Shape and Geometry: This includes the study of the geometry and shape of molecules, bond angles, and hybridization.
Molecular Orbitals: This includes the study of the molecular orbitals, electron density, electron configuration, and the bonding and antibonding orbitals.
Intermolecular Forces: This includes the study of the forces that exist between molecules, such as Van der Waals forces, dipole-dipole forces, and hydrogen bonding.
Spectroscopy: This includes the study of the interaction of electromagnetic radiation with matter, such as absorption and emission spectra, and the use of spectroscopic techniques in molecular structure determination.
Chemical Reactions: This includes the study of how molecules react with each other, reaction mechanisms, and reaction kinetics.
Quantum Mechanics: This includes the study of the fundamental principles and mathematical description of particles and their interactions at a subatomic level.
Computational Chemistry: This includes the use of theoretical methods and computer simulations to study the behavior and properties of atomic and molecular systems.
Orbital Theory: Explains the electronic structure of atoms and molecules by proposing that the electrons exist in certain "orbitals" around the nucleus.
Quantum Mechanics: Studies the behavior of atoms and molecules from a quantum mechanics perspective, which predicts the probability of particles being in certain locations and the energy levels they occupy.
Valence Bond Theory: Describes the chemical bonding in molecules in terms of overlapping of atomic orbitals to form hybrid orbitals, which then combine to form new molecular orbitals.
Molecular Orbital Theory: Treats the entire molecule as a single entity and finds molecular orbitals that can be occupied by electrons from all the atoms in the molecule.
Vibration-Rotation Spectroscopy: A technique used to study the energy levels of the molecular vibrations and rotations of a molecule, in order to deduce its atomic and molecular structure.
Crystallography: A method of determining the atomic and molecular structure of molecules by analyzing the diffraction patterns produced by X-rays or electrons that interact with the crystal.
Electron Paramagnetic Resonance Spectroscopy: Uses magnetic fields to measure the electronic structure of molecules and their interactions with other molecules.
X-ray Absorption Spectroscopy: Examines the electronic structure of materials by measuring the absorption of X-rays by the sample.
X-ray Diffraction: Determines the three-dimensional structure of a molecule by measuring how X-rays are scattered by the material.
Scanning Electron Microscopy: Uses a high-energy beam of electrons to study the morphology of surfaces and determine the atomic and molecular structure of a material.
Transmission Electron Microscopy: Uses a high-energy beam of electrons that pass through a thin sample to study its atomic and molecular structure.
Nuclear Magnetic Resonance Spectroscopy: Uses the magnetic properties of certain atomic nuclei to study the atomic and molecular structure of molecules.
Photoelectron Spectroscopy: Measures the kinetic energy of electrons emitted from a sample when they are hit by photons, which provides information on the electronic structure of the material.
Infrared Spectroscopy: Measures the absorption and transmission of infrared radiation by a material, which can be used to deduce its atomic and molecular structure.
Raman Spectroscopy: Measures the scattering of light off a sample to deduce information about its molecular vibrations and atomic structure.
"The chemical elements are distinguished from each other by the number of protons that are in their atoms."
"The number of protons that are in their atoms."
"Any atom that contains 11 protons is sodium, and any atom that contains 29 protons is copper."
"The number of neutrons."
"Atoms are so small that accurately predicting their behavior using classical physics is not possible due to quantum effects."
"Typically around 100 picometers across."
"More than 99.94%."
"If the numbers of protons and electrons are equal, as they normally are, then the atom is electrically neutral."
"If it has more protons than electrons, it has a positive charge, and is called a positive ion (or cation)."
"If an atom has more electrons than protons, then it has an overall negative charge, and is called a negative ion (or anion)."
"The electrons of an atom are attracted to the protons in an atomic nucleus by the electromagnetic force." "The protons and neutrons in the nucleus are attracted to each other by the nuclear force."
"The nuclear force is usually stronger than the electromagnetic force."
"When the repelling electromagnetic force becomes stronger than the nuclear force."
"The nucleus splits and leaves behind different elements."
"Chemical bonds to form chemical compounds such as molecules or crystals."
"The ability of atoms to attach and detach from each other."
"Chemistry is the discipline that studies these changes."
"A nucleus of protons and neutrons."
"If any are present, have no electric charge."