Worksheet: Development of Atomic Theory Name _ True-False: put a T for True and F for False to the right of each statement

Dalton's atomic theory stated:

atoms are indivisible.

all atoms of the same element are alike.

atoms unite in small, whole number ratios

to form compounds.

The Greek philosopher Democritus was one of the first to suggest the existence of atoms.

The word "atom" means invisible.

A theory is an explanation of observable facts and phenomena.

Aristotle supported the idea of the atom.

From the "gold-foil" experiment it was concluded that the atom is mostly empty space.

Short Answer and Fill in the Blanks:

What must models and theories do in order to remain valid?

a.

b.

The "gold-foil" experiment had the following results: of the alpha particles were deflected, of the alpha particles were reflected, and of the alpha particles passed through the gold foil.