Comprehension Questions Flashcards
Who proposed the idea that matter is composed of small indivisual particles called atoms
Democritis and Leucippus
What ideas did Aristotle propose
He believed that matter was composed of four elements fire earth air and water
In 18u Ed John Dalton published his atomic theory, what did he state?
Dalton stated that all elements are made up of small indivisible particles called atoms
In the scientist that discovered the electron
J.j Thompson
What experiment was JJ Thompson carrying out when he discovered the electron
He was investigating the way gases conduct electricity
In Thompsonโs experiment how did he show the electrons had a negative charge
The electron beam was attracted towards the positive plate therefore they must be chemically charged
The particles were approximately 2000 x lighter than a hydrogen atom and he called them atoms
What did Thompsonโs model of the atom look like
A plum pudding
How was Thompsonโs model of an atom similar to a Christmas pudding
Atoms have negative electrons embedded in the sphere of positive charge just like currents embedded in pudding
Why did Thompson suggest that the atom was neutral
Is contained equal numbers of positive and negative charges and they cancelled each other out
What did Rutherford discover about the atom
The nucleus
Where is nearly all of an atoms mass contained
In the nucleus
In what way was rutherfordโs model of the atom similar to planets revolving around the sun
Positive nucleus similar to sun at center and electrons orbiting around like planets
What part of the atom did James Chadwick discover in 1932
Neutrons
How does the mass of a neutron compare with the mass of a proton
The mass of the proton (1) is equal to the mass of the neutron (1)