"The scientific theory that matter is composed of particles called atoms."
Development of the concept that matter is made up of atoms and molecules, and the study of their behavior and interactions.
Democritus and Leucippus: Greek philosophers who were the first to propose the concept of atoms as the building blocks of matter.
John Dalton: English chemist who formulated the first atomic theory, proposing that atoms were indivisible and had specific masses.
J.J. Thomson: English physicist who discovered the electron and proposed the 'plum pudding' model of the atom.
Ernest Rutherford: New Zealand physicist who discovered the atomic nucleus and proposed the 'planetary' model of the atom.
Robert Millikan: American physicist who determined the charge and mass of the electron using the oil drop experiment.
Niels Bohr: Danish physicist who proposed the 'bohr model' of the atom, which explained the spectra of hydrogen and other elements.
Wolfgang Pauli: Austrian physicist who proposed the exclusion principle, which states that no two electrons can occupy the same quantum state.
Erwin Schrödinger: Austrian physicist who developed the wave equation, which describes the behavior of electrons in atoms.
Werner Heisenberg: German physicist who formulated the uncertainty principle, which states that the position and momentum of a particle cannot both be precisely known.
Paul Dirac: British physicist who developed the concept of anti-particles and contributed to the development of quantum electrodynamics.
Quantum mechanics: A branch of physics that describes the behavior of particles at the atomic and subatomic level.
Nuclear chemistry: The study of the properties and behavior of atomic nuclei.
Radioactivity: The process by which unstable atoms decay and emit radiation.
Isotopes: Atoms of the same element with different numbers of neutrons in their nuclei.
Atomic mass: The mass of an atom, which is determined by the number of protons and neutrons in its nucleus.
Electron configuration: The distribution of electrons in an atom's orbitals.
Periodic table: A chart that organizes the elements based on their atomic number and chemical properties.
Chemical reactions: Processes that involve the rearrangement of atoms and molecules.
Nuclear reactions: Processes that involve the transformation of atomic nuclei.
Fusion and fission: Two types of nuclear reactions that release large amounts of energy.
Democritus' Atomic Theory: This theory was proposed by Democritus in the 5th century BC. According to this theory, all matter is composed of indivisible and indestructible particles called atoms.
Dalton's Atomic Theory: This theory was proposed by John Dalton in the early 19th century. According to this theory, all matter is composed of atoms, which are indivisible and can neither be created nor destroyed. Atoms of the same element are identical in size, shape, and chemical properties.
Thomson's Atomic Theory: This theory was proposed by J.J. Thomson in the late 19th century. According to this theory, atoms are composed of smaller particles called electrons which are embedded in a positively charged sphere. This was known as the Plum Pudding Model.
Rutherford's Atomic Theory: This theory was proposed by Ernest Rutherford in the early 20th century. According to this theory, atoms have a central nucleus composed of positively charged protons and neutral neutrons. Electrons orbit the nucleus in distinct energy levels.
Bohr's Atomic Theory: This theory was proposed by Niels Bohr in the early 20th century. According to this theory, electrons follow specific energy levels around the nucleus, and they can jump between these levels by absorbing or emitting energy. This theory laid the foundation for quantum mechanics and the modern understanding of atoms.
Quantum Mechanics Theory: This theory describes the behaviors of atoms and subatomic particles based on probability and wave-particle duality. It is widely accepted as the current model to explain the behavior of atoms.
Atomic and Molecular Spectroscopy: This field of study involves the analysis of the interaction between light and atoms/molecules. It provides insights into the behavior and properties of atoms and molecules.
Electron Microscopy: This technique involves the use of electron beams to study the structure of atoms and molecules at a very high resolution. This technology has revolutionized our understanding of the atomic world.
Atomic Power and Nuclear Reactors: This is the application of atomic theory in generating electrical power using the energy released by nuclear reactions. This application has become an essential part of modern energy production.
Modern Atomic Theory: This theory encompasses all aspects of atomic physics and chemistry that have been discovered so far. It includes the recent discoveries of subatomic particles such as quarks and leptons, and the study of dark matter, which is the mysterious matter that makes up the majority of the universe's mass.
"The concept gained scientific credence in the 18th and 19th centuries."
"Scientists found it could explain the behaviors of gases."
"It could explain how chemical elements reacted with each other."
"By the end of the 19th century, atomic theory had gained widespread acceptance."
"The term 'atom' comes from the Greek word atomos, which means 'uncuttable'."
"John Dalton applied the term to the basic units of mass of the chemical elements."
"He believed that chemical atoms are the fundamental particles in nature."
"It was another century before scientists realized that Dalton's so-called atoms have an underlying structure of their own."
"Particles which are truly indivisible are now referred to as 'elementary particles'."
"Atomic theory proposes that matter is composed of particles called atoms."
"Scientists found that atomic theory could explain the behaviors of gases."
"Scientists found that atomic theory could explain how chemical elements reacted with each other."
"By the end of the 19th century, atomic theory had gained widespread acceptance."
"The term 'atom' comes from the Greek word atomos, which means 'uncuttable'."
"John Dalton attributed the name 'atom' to the basic units of mass of the chemical elements."
"He believed that chemical atoms are the fundamental particles in nature."
"It was another century before scientists realized that Dalton's so-called atoms have an underlying structure of their own."
"Particles which are truly indivisible are now referred to as 'elementary particles'."
"Scientists found that atomic theory could explain the behaviors of gases and how chemical elements reacted with each other."