Advertisement Upgrade to remove ads


greek - substances - earth, air, fire, water
- essences - wet, dry, hot, cold









human body is composed of what 4 elements


ionizing radiation




who invented the periodic table


einstein's equation of relativity


atomic mass unit

one atomic mass unity is equal to 1/12 the mass of a carbon-12 atom

atomic mass


atomic mass number




alpha particles


beta particles




amn of a proton


amn of a neutron


amn of an electron


what is amu based on


atom after emissions (alpha and beta)


what is half life


principle quantum number


outer shell max


does radiation ever reach zero


nuclear stability


xrays vs gamma rays


centripital force


symbol for atomic number



1913, improved rutherfords description of the atom, a miniature solar system in which the electrons revolved about the nucleus in prescribed orbits or energy levels.




late 1890's he described the atom as looking something like a plum pudding, where the plums represented negative electric charges (electrons) and the pudding was a shapeless mass of uniform positive electrification.


1911 - disproved thomson's model of the atom, introduced the nuclear model, which described the atom as containing a small, dense, positively charged center surrounded by a negative cloud of electrons. he called the center of the atom the nucleus


1808 - school teacher - elements could be classified according to integral values of atomic mass
an element was composed of identical atoms that reacted the same way, chemically

smallest atom


wavelength of red


wavelength of violet


rf measured in


xrays measured in


visible light measured in





showed elements were arranged in order of increasing atomic mass, a periodic repetition of similar chemical properties occurred

what are the fundamental particles of an atom

electron, proton, neutron

what is an atom?

the smallest particle that has all the properties of an element

essentially empty space

what is the mass of a proton? neutron? electron?

proton - 1.673 x 10^-27 kg
neutron 1.675 x 10^-27 kg (slightly heavier)
electron 9.1 x 10^-31 kg

in their normal state, what is the charge of an atom


what is ionization

the removal of an orbital electron from an atom

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 above 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

NEW! Voice Recording