Atomic Theory (QUIZ 1) Flashcards
Understand the progression of the atomic theory.
Which scientist discovered subatomic particles using a cathode ray tube?
Thomson
Which scientist discovered the nucleus?
Rutherford
Which scientist showed that electrons emit energy when they fall back down to ground state?
Bohr
Which scientist discovered atoms of different elements are different from one another?
Dalton
Which scientist bombarded gold foil with alpha particles?
Rutherford
Which scientist clarified that electrons occupied specific orbits or energy levels?
Bohr
Which scientist called the smallest particle of an object, “atomos”?
Democritus
Which scientist discovered that electrons move in regions of space that can be defined by a wave equation?
Schrödinger
Which scientist said “compounds are formed by the joining of atoms of two or more elements”?
Dalton
What was Thomson’s model sometimes called?
Plum pudding model
What was Rutherford’s model sometimes called?
Planetary model
What is the modern model called?
Wave model
Which scientist proposed that atoms were indivisible and indestructible (later disproved)?
Dalton
Who disproved the proposition that atoms were indivisible and indestructible?
Thomson
Which scientist asked “Could matter be divided into smaller and smaller pieces forever, or was there a limit to the number of times a piece of matter could be divided”?
Democritus
What was the standard, wide-spread, and more respected theory favoured by eminent philosophers Aristotle and Plato that was ultimately incorrect and caused Democritus’ theory to be buried for 2000 years?
Four Classical Elements Theory
Which scientist said that “compounds are formed by the joining of atoms of two or more elements”?
Dalton
Why was Thomson’s model named as it was?
It was named the plum pudding theory for it theorized that atoms were made from a positively charged substance with negatively charged electrons scattered throughout, akin to raisins in pudding.
How did Thomson discover “corpuscles”?
While studying the passage of a cathode ray through low-pressure gas, he discovered that as the current passed through the gas, it gave off rays of negatively charged particles, which was surprising as the gas was widely known to be neutral. He deduced the rays were more than just light as they bent with magnets (only charged particles respond to magnetic fields). He then deduced that the negative charges came from within the atom, and that a particle smaller than an atom had to exist. He dubbed the negatively charged particles “corpuscles”, later changed to “electrons”.
How did Rutherford discover the nucleus?
He experimented by firing positively charged alpha particles at 2000 atom thin gold foil. While most passed through without changing course, some bounced away as if they had hit solids. He knew that positive repels positive, and thus concluded that most of the gold atoms in the sheet were empty space and that an atom had a small, dense, positively charged center that repelled his alpha particles. He dubbed that center the “nucleus”, and stated that the negatively charged particles (electrons) were scattered outside the nucleus at the atom’s edge.
How did Bohr refine Rutherford’s model?
He analyzed the pattern of colours of light emitted from heated hydrogen atoms and realized that light was emitted when they hit ground state. He also
Why is Thomson’s model named as it is?
It is named the plum pudding model as it theorized that atoms were made of a positively charged substance with negatively charged particles scattered all-throughout, akin to raisins in pudding.
How did Thomson discover “corpuscles”?
In an experiment observing the way cathode rays travel through low-pressure gas, he discovered that as the ray passed through the gas, it gave off rays of negatively charged particles. These rays were found to be more than just light as they were affected by magnets (only charged particles respond to magnetic fields). He surmised that the negative charge came from within the atom, disproving Dalton’s idea that atoms were indivisible and indestructible. He dubbed the negatively charged particles “corpuscles” and they were later called “electrons”. Since the gas was neutral, he also reasoned positively charged particles must exist in the atom.
How did Rutherford discover the nucleus?
He was experimenting by firing small positively charged alpha particles at gold foil that was 2000 atoms thick. While most passed through, some reflected as though they had hit solids. With his prior knowledge that positive repels positive, he surmised that most of the gold was open space and there was a center that was dense and positively charged which repelled his alpha particles.
