proposed that all matter was composed of atoms, indivisible and indestructible building blocks. While all atoms of an element were identical, different elements had atoms of differing size and mass.
Daltons Atomic Theory
Dalton's atomic theory proposed that all matter was composed of atoms, indivisible and indestructible building blocks. While all atoms of an element were identical, different elements had atoms of differing size and mass.
his research in cathode rays led to the discovery of the electron, and he pursued further innovations in atomic structure exploration.
Cathode Ray Tube Experiment
J.J. Thomson's experiments with cathode-ray tubes showed that all atoms contain tiny negatively charged subatomic particles or electrons. Thomson proposed the plum pudding model of the atom, which had negatively-charged electrons embedded within a positively-charged "soup."
Plum Pudding Model
a model of atomic structure proposed by J.J. Thomson had discovered that atoms are composite objects, made of pieces with a positive and negative charge and that the negatively charged electrons within the atom were very small compared to the entire atom.
Gold Foil Experiment
Rutherford's Gold Foil Experiment proved the existence of a small massive center to atoms, which would later be known as the nucleus of an atom
Oil Drop Experiment (1909)
this was performed by Robert A. Millikan and Harvey Fletcher to measure the elementary electric charge (the charge of the electron) The experiment entailed observing tiny electrically charged droplets of oil located between two parallel metal surfaces, forming the plates of a capacitor.
he succeeded in precisely determining the magnitude of the electron's charge.
he was the first to discover that atoms have a small charged nucleus surrounded by largely empty space, and are circled by tiny electrons, which became known as the Rutherford model (or planetary model) of the atom
proposed a theory for the hydrogen atom based on quantum theory that energy is transferred only in certain well-defined quantities. Electrons should move around the nucleus but only in prescribed orbits. When jumping from one orbit to another with lower energy, a light quantum is emitted. Bohr's theory could explain why atoms emitted light in fixed wavelengths.