Scientist/ Atomic Theory Flashcards
Aristotle named atoms atoms
False/
Who proposed that matter was composed of tiny indivisible particles?
Democritus
Aristotle was a Greek philosophers thought that matter was composed of four elements: air, earth, fire, and water
True
Which scientist described a positively charged core (“nucleus”) in the middle of a lot of empty space?
Rutherford
Which scientist described an atom made of a solid positively charged substance with electrons dispersed throughout it?
Thomson
Which scientist described the existence of the neutron?
(neutral particles in the nucleus of an atom)
Chadwick
J. J. Thomson’s plum pudding model of the atom addressed the issue of why
electrons are electrically charged.
Rutherford expected alpha particle to travel almost straight through a target of gold fol. The results of his gold foil experiment did not support
Thomson’s plum pudding theory
James Chadwick showed that the nucleus also contained a neutral subatomic particle known as the
Neutron
(Billiard Ball Model)
_______ states that an atom is a uniform, solid sphere
John Dalton
Atoms are indivisible and indestructible
John Dalton
Atoms of the same element are identical
John Dalton
Atoms of different elements combine in simple proportions or ratios to create a compound
John Dalton
(Discovered radioactivity)
__________ stated that spontaneous emission of radiation from the nucleus
Henri Becquerel
States that’s there are three types of Decays:
- alpha (a) - positive
- beta (B) - negative
- gamma (Y) - neutral
Henri Becquerel
(Cathode Ray Tube Experiments)
__________ states there’s beam of negative particles
J. J. Thomson
(Discovered Electron)
- negative particles within the atom
J. J. Thomson
(Discovered the nucleus) (gold foil experiment)
- dense, positive charge in the center of the atom
Ernest Rutherford
(Nuclear Model)
- dense, positive nucleus surrounded by negative electrons
Ernest Rutherford
(Bright-Line Spectrum)
-tried to explain presence of specific colors in hydrogen’s spectrum
Niels Bohr
•(Joliot-Curie Experiments)
- Radiation bombardment produces a “new” particle
James Chadwick
Nature has two forces - conflict and harmony
Aristotle
________ claimed that each of the elements move naturally to their “proper place,” where it will be “at rest”
Aristotle
Aristotle believed there was a fifth element called “ether” which solely comprised the heavens
True
Who claimed chem was a mixture of science and mysticism
Alchemy
All matter is made of tiny pieces
Democritus and J Daltion
Matter is composed of atoms, which move through empty space
Democritus
An atom cannot be divided
Democritus and Daltion
An atom cannot be created
Democritus and J Daltion
An atom cannot be destroyed
Democritus and J J Daltion
Different atoms combine in whole number ratios to form compounds
J Daltion
The properties of atoms vary based on the shape, size and movement
Democritus
Different kinds of atoms come in different sizes and shapes
Democritus
Who originally proposed the concept that matter is composed of tiny, indivisible particles?
Democritus
Whose work is credited with being the beginning of modern atomic theory?
John Dalton
Explain why Democritus was unable to experimentally verify his ideas.
He lacked the tools necessary to demonstrate the existence of atoms
What was Aristotle’s objection to the atomic theory?
There was no empty space therefore atoms cannot move through space
State the main points of Dalton’s atomic theory using your own words. Which parts of Dalton’s theory were later found to be erronous? Explain why.
One of Dalton’s atomic theory’s state that an atom is the smallest particle in a chemical reaction , Substance are made of atoms, an atom can’t be destroyed or made, & diffrent atom elements can be mixed. Later an it was found that atomes are not the smalest particles becuse they can be divided into electrons, neutrons, & Protons. And it’s also false that diffrent atom elements can be mixed, Some compounds will turn into gas or vapor.
Explain why atoms are electrically neutral.
The (+) charge of the nucleus balances the (-) charge of electrons leaving the atom equal, no change on the atom
Cathode-Ray Tubes Which subatomic particle was discovered by researchers working with cathode-ray tubes?
Electron were a beam of negative particles by J J Thomason
Briefly explain how Rutherford discovered the nucleus.
By an experiment to prove that atoms were made up of just empty space so (+) charge particles would flow through a golden foil, but the alpha (+) scattered, it proved that there was a core in the atom (nuclear charge)
What caused the deflection of the alpha particles in Rutherford’s gold foil experiment?
The dense core in the nucleus/(+) charges
