Like this study set? Create a free account to save it.

Sign up for an account

Already have a Quizlet account? .

Create an account

discovery of atomic structure

Dalton's conclusions for the existence of atoms are based on observations of how matter behaves
Atoms are too small to be seen
How did he, and other scientists of the time, "know" atoms exist?

Cathode Rays

In the mid 1800s it was discovered that radiation was produced when high voltage is applied to electrodes in a partially evacuated glass tube.

The rays themselves are invisible, however they cause certain materials, including glass, to fluoresce.

The rays were also observed to be deflected by the presence of a magnetic field.

J.J. Thompson

In 1897 published a paper that concluded, from his observations, that the radiation was a stream of negatively charged particles.
made paper that is generally accepted as the discovery of the electron.

Robert Millikan

went to University of Chicago, performed a series of experiments that determined the charge and mass of an electron.


1.602e-19 Coulombs


9.10e-28 grams


spontaneous emission of radiation

Henri Becquerel

French scientist discovers in 1896 that a Uranium compound spontaneously emits high-energy radiation

earnest rutherford

discovers three types of radiation
Alpha (a)
Beta (b)
Gamma (g)


type of radiation
Fast moving particles called ... particles.
Charge; 2+
Mass; about 7400 times that of an electron


type of radiation
Fast moving particles called ... particles that are really high speed electrons
Charge; 1-
Mass; about 7400 times that of an electron


type of radiation
High energy radiation similar to X-rays.
Does not consist of particles and does not have a charge

atoms are composed of smaller particles

The discovery of the electron and observation that some compound spontaneously emit radiation suggests that...

atoms are a uniform sphere of positive charge with negatively charged electrons embedded inside

J.J. Thompson proposed that...
He further said that because electrons are so small they contribute virtually nothing to the over mass of the atom itself.

J.J. thompson

made model of atom become know as the "plumpudding" model


negativly charged electrons in plum pudding model


possitivly charge spread throughout the sphere

The gold foil experiment

consisted of a beam of alpha particles shot at an extremely thin foil of gold


performed experiment known as gold foil experiment to tst thompson's plum pudding model


in the gold foil experiment-Most of the mass of each gold atom and all of its positive charged are in a small, very dense, region called ...


In nucleus-Positively charged 1919 by ...

neutrons/james chadwick

in nucleus-neutral... in 1932 by...

empty space

most of the total volume of the atom which electrons move

Please allow access to your computer’s microphone to use Voice Recording.

Having trouble? Click here for help.

We can’t access your microphone!

Click the icon above to update your browser permissions and try again


Reload the page to try again!


Press Cmd-0 to reset your zoom

Press Ctrl-0 to reset your zoom

It looks like your browser might be zoomed in or out. Your browser needs to be zoomed to a normal size to record audio.

Please upgrade Flash or install Chrome
to use Voice Recording.

For more help, see our troubleshooting page.

Your microphone is muted

For help fixing this issue, see this FAQ.

Star this term

You can study starred terms together

Voice Recording