Scientific Models of the atom 1-12-18 Jackson 1st hour
2 months ago
Democritus He proposed that matter could NOT be divided into smaller particles; He claimed that matter was made up of small, hard particles that he called "atoms"
John Dalton Dalton created the very first atomic theory. Dalton viewed atoms as tiny, solid balls. Daltons theory had 4 parts to it: 1) Atoms are tiny, invisible particles 2) Atoms of one element are all the same 3) Atoms of different elements are different 4) compounds form by combining atoms
J.J. Thomson He was the first scientist to show that the atom was made of even smaller things. He also proposed the existence of the POSITIVE particle. His atomic model was known as the "raisin bun model" Atoms are made mostly out of POSITIVE charged material, like dough in a bun. The NEGATIVE charged electrons are found inside the POSITIVE dough.
Ernest Rutherford He discovered PROTONS and the NUCLEUS. He showed that atoms have POSITIVE particles in the center, and are MOSTLY EMPTY SPACE. He called these POSITIVE PROTONS . He called the center of the atom the NUCLEUS.
Niels Bohr He improved Rutherford's model. He proposed that electrons move around the nucleus in specific layers, or shells. Every atom has a specific number of electron shells/layers.
James Chadwick He discovered NEUTRONS. Working with Rutherford, he discovered particles with no charge (neutrons). Neutrons are also found in the nucleus.
THE Electron cloud The new atomic model has electrons moving around the nucleus in a cloud. It is impossible to know where an electron is at any given time.
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