In 1897 he showed that
cathode rays
(radiation emitted when a voltage is applied between two metal plates inside a glass tube filled with low-pressure gas) consist of particles – electrons – that conduct electricity. Thomson also concluded that electrons are part of atoms.
What did JJ Thomson discover?
In 1897 Thomson discovered
the electron
and then went on to propose a model for the structure of the atom. His work also led to the invention of the mass spectrograph.
Who is JJ Thomson and what did he discover?
Thomson, in full Sir Joseph John Thomson, (born December 18, 1856, Cheetham Hill, near Manchester, England—died August 30, 1940, Cambridge, Cambridgeshire), English physicist who helped revolutionize the knowledge of atomic structure by his discovery of
the electron (1897)
.
Why was JJ Thomson’s discovery important?
J. J. Thomson took science to new heights with his 1897
discovery of the electron – the first subatomic particle
. He also found the first evidence that stable elements can exist as isotopes and invented one of the most powerful tools in analytical chemistry – the mass spectrometer.
What did JJ Thomson discover about the atomic model?
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.”
Why was JJ Thomson’s model wrong?
Thomson’s atomic model
failed to explain how the positive charge holds on the electrons inside the atom
. It also failed to explain an atom’s stability. The theory did not mention anything about the nucleus of an atom. It was unable to explain the scattering experiment of Rutherford.
What was Rutherford’s model called?
Rutherford model, also called
Rutherford atomic model, nuclear atom, or planetary model of the atom
, description of the structure of atoms proposed (1911) by the New Zealand-born physicist Ernest Rutherford.
What is an interesting fact about JJ Thomson?
In 1906 he
demonstrated that hydrogen had only one electron per atom
. He designed instruments to pas cathode rays through a magnetic field and he was the first to determine the mass-to-charge ratio of cathode rays. In 1908 he was knighted for his contributions to science and in 1912 he received the Order of Merit.
Why did JJ Thomson discovered the electron?
In 1897, J.J. Thomson discovered the electron by
experimenting
with a Crookes, or cathode ray, tube. … Thomson realized that the accepted model of an atom did not account for negatively or positively charged particles. Therefore, he proposed a model of the atom which he likened to plum pudding.
What scientists did JJ Thomson work with?
In addition to Thomson himself, six of his research assistants (
Charles Glover Barkla, Niels Bohr, Max Born
, William Henry Bragg, Owen Willans Richardson and Charles Thomson Rees Wilson) won Nobel Prizes in physics, and two (Francis William Aston and Ernest Rutherford) won Nobel prizes in chemistry.
Who was Rutherford’s student?
By 1911, after studying the deflection of alpha particles shot through gold foil, he had established the nuclear theory of the atom. One of his students,
Niels Bohr
, used Rutherford’s model of the atom to describe the hydrogen spectrum in terms of the quantum theory.
What are the contribution of JJ Thomson?
A series of experiments with cathode rays he carried out near the end of the 19th century led to his
discovery of the electron
, a negatively charged atomic particle with very little mass. Thomson received the Nobel Prize in Physics in 1906 for his work exploring the electrical conductivity of various gases.
What was Thomson’s model called?
Popularly known as
the plum pudding model
, it had to be abandoned (1911) on both theoretical and experimental grounds in favour of the Rutherford atomic model, in which the electrons describe orbits about a tiny positive nucleus.
What was Dalton’s model?
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.
Who discovered the electron?
Although
J.J. Thomson
is credited with the discovery of the electron on the basis of his experiments with cathode rays in 1897, various physicists, including William Crookes, Arthur Schuster, Philipp Lenard, and others, who had also conducted cathode ray experiments claimed that they deserved the credit.
Is cathode a ray?
Cathode rays (also called an electron beam or an e-beam) are
streams of electrons observed in vacuum tubes
. … Cathode rays are so named because they are emitted by the negative electrode, or cathode, in a vacuum tube. To release electrons into the tube, they must first be detached from the atoms of the cathode.
