Post by ChairmanWalker on Nov 11, 2011 6:08:18 GMT -5
The Development of Atomic Theory – John Dalton
In the 5th century BCE a Greek philosopher, Democritus proposed the idea that all matter was composed of small indivisible particles called. A French chemist, Joseph Louis Proust, proposed in 1799 that if a compound is broken down into its constituent elements, then the masses of the constituents have the same proportions, regardless of the quantity or source of the substance.
Next an English chemist, William Prout, observed that the atomic weights of all elements of the time were whole multiplications of the mass of hydrogen, making it the only fundamental element and that all other elements were groupings of varying numbers of hydrogen atoms. Ernest Rutherford believed that the majority of the mass of an atom and the positive charge is concentrated in a very small fraction of its volume, which he assumed was at the center, now called the nucleus.
In 1918, Rutherford hit nitrogen has with alpha particles and observed hydrogen nuclei being emitted from the gas. He concluded from this that the hydrogen nuclei emerged from the nuclei of the nitrogen atoms themselves, effectively splitting the atom. In 1924, Louis de Broglie proposed that all moving particles exhibit a degree of wave-like movement. Erwin Schrödinger explored whether or not the movement of an electron in an atom could be better explained as a wave rather than as a particle. Schrödinger's equation, published in 1926, describes an electron as a wavefunction instead of as a point particle.
John Dalton was an English chemist, he printed an early table of relative atomic weights. Six elements were on this table; hydrogen, oxygen, nitrogen, carbon, sulfur and phosphorus with the hydrogen atom label with a mass of one. He believed that all atoms of any given element are identical and that different elements can form compounds together.
He also believed that atoms cannot be created, divided into smaller parts or destroyed in chemical processes, they can only change the way atoms are grouped together. His earlier findings were accomplished by a series of studies conducted on water, ammonia and carbon dioxide, giving him also a basis for theory on compounds. His theory on relative mass and element compounds gave a basis for further findings and exploration in atomic theory and his findings have since been evident in atomic theory.
Bibliography
www.chemheritage.org/classroom/chemach/periodic/dalton.html
abyss.uoregon.edu/~js/21st_century_science/lectures/lec05.html
dl.clackamas.edu/ch104-04/dalton%27s.htm
In the 5th century BCE a Greek philosopher, Democritus proposed the idea that all matter was composed of small indivisible particles called. A French chemist, Joseph Louis Proust, proposed in 1799 that if a compound is broken down into its constituent elements, then the masses of the constituents have the same proportions, regardless of the quantity or source of the substance.
Next an English chemist, William Prout, observed that the atomic weights of all elements of the time were whole multiplications of the mass of hydrogen, making it the only fundamental element and that all other elements were groupings of varying numbers of hydrogen atoms. Ernest Rutherford believed that the majority of the mass of an atom and the positive charge is concentrated in a very small fraction of its volume, which he assumed was at the center, now called the nucleus.
In 1918, Rutherford hit nitrogen has with alpha particles and observed hydrogen nuclei being emitted from the gas. He concluded from this that the hydrogen nuclei emerged from the nuclei of the nitrogen atoms themselves, effectively splitting the atom. In 1924, Louis de Broglie proposed that all moving particles exhibit a degree of wave-like movement. Erwin Schrödinger explored whether or not the movement of an electron in an atom could be better explained as a wave rather than as a particle. Schrödinger's equation, published in 1926, describes an electron as a wavefunction instead of as a point particle.
John Dalton was an English chemist, he printed an early table of relative atomic weights. Six elements were on this table; hydrogen, oxygen, nitrogen, carbon, sulfur and phosphorus with the hydrogen atom label with a mass of one. He believed that all atoms of any given element are identical and that different elements can form compounds together.
He also believed that atoms cannot be created, divided into smaller parts or destroyed in chemical processes, they can only change the way atoms are grouped together. His earlier findings were accomplished by a series of studies conducted on water, ammonia and carbon dioxide, giving him also a basis for theory on compounds. His theory on relative mass and element compounds gave a basis for further findings and exploration in atomic theory and his findings have since been evident in atomic theory.
Bibliography
www.chemheritage.org/classroom/chemach/periodic/dalton.html
abyss.uoregon.edu/~js/21st_century_science/lectures/lec05.html
dl.clackamas.edu/ch104-04/dalton%27s.htm
