According to atomic theory, matter is made up of indivisible particles known as atoms.
It suggests that
atoms interact in predetermined ratios to form compounds and experience chemical reactions. It was
developed by scientists like John Dalton. The theory changed as a result of J.J. Niels Bohr, Ernest
Rutherford, and Thomson contributed to the development of the current theory of atomic structure,
which holds that atoms are made up of an electron-orbiting nucleus made up of protons and neutrons.
This idea is further refined by quantum mechanics. Chemistry relies heavily on atomic theory, which
offers a framework for comprehending the behavior and composition of matter at the smallest scale.
2. John Dalton proposed basic ideas regarding the nature of matter in his early 19th-century work,
Dalton's Atomic Theory. It implies that atoms, the fundamental building blocks of all elements, are
indivisible, unbreakable particles. Dalton also proposed that different elemental atoms have unique
masses and mix in predetermined ratios to form compounds. Dalton's idea established the foundation
for contemporary atomic theory, emphasizing the importance of atoms in comprehending the makeup
and behavior of matter, even though some parts have been altered with developments.
3. The atom's plum pudding model was put forth by J.J. Thomson in the year 1904. This model suggested
a break from the earlier idea of indivisible atoms, proposing a more dynamic structure: the atom is
envisioned as a positively charged sphere, with negatively charged electrons embedded within it like
"plums" in a "pudding." Thomson's model laid the groundwork for later advancements in atomic theory,
most notably Ernest Rutherford's discovery of the nucleus, which allowed scientists to comprehend the
internal workings of the atom.
4. The word "nucleus" was first used by Ernest Rutherford in 1911. Rutherford identified the nucleus—a
tiny, dense, positively charged core found in all atoms—through the gold foil experiment. This crucial
experiment demonstrated that electrons orbit around this tiny region, which contains the majority of
the atom's mass and positive charge. Rutherford's seminal work transformed our knowledge of atomic
structure, paving the way for the creation of the nuclear model and modern physics. The word "nucleus"
appropriately describes this structure's pivotal, crucial function inside the atom.
5.
Democritus (460–370 BCE):
Proposed the idea of atomos, indivisible particles that make up matter.
John Dalton (1803–1807):
Formulated Dalton's Atomic Theory, suggesting atoms are indivisible and combine in simple ratios.
J.J. Thomson (1897):
Discovered electrons through cathode ray experiments, proposing the "plum pudding" model.
Ernest Rutherford (1909):
Conducted the gold foil experiment, leading to the discovery of the atomic nucleus.
Niels Bohr (1913):
Introduced the Bohr model, with electrons in quantized orbits around the nucleus.
Louis de Broglie (1924):
Proposed wave-particle duality, suggesting electrons have both wave and particle properties.
Werner Heisenberg (1925):
Formulated the Heisenberg Uncertainty Principle, challenging precise simultaneous measurement of
particle properties.
Erwin Schrödinger (1926):
Developed the wave equation, forming the basis of quantum mechanics and introducing electron
wavefunctions.
James Chadwick (1932):
Discovered the neutron, completing the atomic model with protons, neutrons, and electrons.
Modern Synthesis (Mid-20th Century Onward):
Integration of quantum mechanics and wave-particle duality, leading to the electron cloud model and a
comprehensive understanding of atomic structure.
