"A particle that consists of a nucleus of protons and neutrons surrounded by an electromagnetically-bound cloud of electrons."
The arrangement of atoms in materials and their effects on properties.
Electromagnetic radiation: The behavior and properties of electromagnetic radiation, including wavelength, frequency, and energy.
Black-body radiation: The emission of radiation from an object due to its temperature, as described by Planck's law.
Photoelectric effect: The emission of electrons from a material when it is exposed to light.
Wave-particle duality: The concept that electromagnetic radiation behaves as both waves and particles.
Bohr model of the atom: A model of the atom as a central nucleus surrounded by discrete energy levels or shells of orbiting electrons.
Atomic spectra: The specific wavelengths of light emitted or absorbed by atoms as they undergo transitions between energy levels.
Quantum mechanics: The theory that describes the behavior of matter and electromagnetic radiation at the atomic and subatomic level.
Schrödinger equation: The mathematical equation that describes the behavior of electrons in atoms and molecules.
Quantum numbers: The set of numbers that describe the energy and location of electrons within an atom.
Pauli exclusion principle: The principle that no two electrons in an atom can have the same set of quantum numbers.
Electron configuration: The arrangement of electrons in an atom's orbitals.
Periodic table: A table that arranges elements by their atomic number and chemical properties.
Isotopes: Different versions of an element with the same number of protons but a different number of neutrons.
Radioactivity: The spontaneous emission of radiation from unstable atomic nuclei.
Nuclear binding energy: The amount of energy required to separate the individual nucleons in a nucleus.
Mass-energy equivalence: The principle that mass and energy are interchangeable.
Fission and fusion reactions: The processes of splitting or combining atomic nuclei to release energy.
Half-life: The time it takes for half of the radioactive material in a sample to decay.
Radioactive decay modes: The different ways in which radioactive isotopes decay, including alpha, beta, and gamma decay.
Radioactive decay series: The sequence of decay products resulting from the decay of a radioactive isotope.
Crystalline: This is the most common atomic structure found in materials engineering. It is characterized by an ordered, repeating arrangement of atoms in a three-dimensional lattice. Examples include diamonds and table salt.
Amorphous: This type of atomic structure lacks a regular, repeating pattern. These materials have more disordered, random placement of atoms, like glass or plastics.
Polycrystalline: A material with multiple crystalline structures, joined through grain boundaries: Regions of disorder.
Face-centered cubic (FCC): Each atom in an FCC structure is surrounded by 12 nearest neighbors, giving it a density of 74% relative to the closest-packed arrangement.
Body-centered cubic (BCC): Each atom in a BCC structure is surrounded by eight nearest neighbors, giving it a density of 68% relative to the closest-packed arrangement.
Hexagonal close-packed (HCP): Each atom in an HCP structure is surrounded by 12 nearest neighbors, giving it a density of 74% relative to the closest-packed arrangement, but the atoms are packed in a hexagonal arrangement.
Diamond cubic: In a Diamond cubic structure, the atoms are arranged in a tetrahedral pattern with each atom covalently bonded to its four nearest neighbours, hence has a tetragonal symmetry.
"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."