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

Sign up for an account

Already have a Quizlet account? .

Create an account


the smallest particle of an element that retains its identity in a chemical reaction

Dalton's atomic theory

the first theory to releate chemical changes to events at the atomic level; described the structure and chemical reactivity of matter in terms of atoms


Greek philosopher who was among the first to suggest the existence of atoms

Scanning Tunneling microscope

an instrument used to generate images of individual atoms


negatively charged subatomic particles

cathode ray

stream of electons produced at the negative electrode of a tube containing a gas at low pressure


positively charged subatomic particles


subatomic particles with no charge


the central core of the atom which is made up of protons and neutrons

atomic number

the number of protons in the nucleus of an atom of an element

mass number

the total numbe rof protons and neutrons in the nucleus of an atom


atoms of the same element have the same atomic number of different atomic masses due to a different number of neutrons

atomic mass unit (amu)

a unit of mass equal to one-twelfth the mass of a carbon-12 atom

atomic mass

the weighted average of the masses of the isotopes of an element

periodic table

an arrangement of elements in which the elemtns are separated into groups based on a set of repeating properties


a horizontal row of elements in the periodic table


a vertical column of elements in the periodic table; the constiuent elements of a group have similar chemical and physical properties

Atomic number

a number equal to the number of protons as well as the number of electrons in an atom

Number of neutrons

Equal to the mass number minus the atomic number

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