Name: _____________________________
Per:______
Date:__________
WS 2:1 Subatomic Particles & Models of the Atom
Chemists in History - Write the name of the chemist who proposed each of the ideas listed below. Some names
may be used more than once.
_____________________ 1. Stated that matter is neither created nor destroyed in chemical reactions.
_____________________ 2. Stated that a given compound always has the same relative number and
kinds of atoms.
_____________________ 3. Determined that a cathode ray is made of electrons.
_____________________ 4. Understood the atom to have a central nucleus with electrons orbiting
around in fixed paths like planets around the sun.
_____________________ 5. Stated that all atoms of a given element are identical, but they differ from
those of other elements.
_____________________ 6. Stated that all matter is composed of tiny, indivisible particles called atoms.
_____________________ 7. Used Gold Foil to determine that all the positive matter (protons) is
concentrated into a very small, very dense nucleus and that most of the
atom is empty space.
Experiments about the Atom, Fill in the blanks with the appropriate word.
14. Dalton Combined all known information about atoms up to that time into one theory that he called
______________________ ______________________. This theory had 4 parts: All ______________ are
made of ______________________. All atoms in an element are ____________________. Atoms are not
______________________ or ___________________ in chemical reactions, and _______________ have
definite whole number ratios of elements.
15. In Thompson’s experiment, the cathode ray is deflected by a _______________ charged magnet, this
indicated that the ray had ____________________ charge.
16. From these observations Thompson concluded that a cathode ray is made of a beam of
____________________. Because the beam of electrons pushed a paddle weal, Thompson concluded that
electrons must have _________________.
19. Rutherford used alpha particles in his Gold Foil experiment. Because the alpha particles are relatively
large and positive that fact that most of them proceeded straight through the foil proved that the atom
is mostly ____________ space. Some of the positive alpha particles deflected directly
back toward the source which indicated that the nucleus was _______________________ charged
Thus, Rutherford is credited with discovering the ___________________ of an atom.
Identify the model of the atom, its creator, and why it is incorrect:
Model:__________________
Model:__________________
Creator:_________________
Creator:_________________
Why its incorrect:
Paragraph: Wright a paragraph summating the birth of atomic theory up to and including Daltons atomic theory.
Include ALL the following words/phrases and UNDERLINE them in your passage.
-
John Dalton
All elements are made of atoms
All atoms in an element are identical.
Compounds have definite whole number
ratios of elements.
Atoms are not created or destroyed in
chemical reactions.
J. J. Thompson
Cathode ray tube
-
electrons
negative charge
gold foil experiment
Rutherford
empty space