Matter
anything that has mass and takes up space
matter
solid to liquid
melting
found in the nucleus of an atom and has a positive charge
protons
found in the nucleus of an atom and is neutral
neutron
discovered the electron
JJ Thomson
states of matter
solid, liquid and gas
liquid to solid
freezing
found circling the nucleus of an atom and has a negative charge
electron
two or more substances that are not chemically combined with each other and can be separated by physical means.
mixtures
Electrons travel in fixed orbits around the nucleus at different energy levels.
Bohr Model
particles are packed tightly together
solid
evaporation/boiling
atomic number of an atom equals to
#of protons or #number of electrons
to differentiate homogenous from heterogeneous scientists ask this question
is it uniform though out?
All matter is composed of small, indivisible particles called atoms.
Dalton
indefinite shape and definite volume
liquid
gas to solid
deposition
atomic mass (mass number) of an atom equals
neutrons PLUS protons
to separate homogenous mixture from a pure substance, scientists ask this question
can it be separated by physical means?
Discovered the nucleus using the Gold Foil experiment
Ernest Rutherford
oxygen has ____________ volume and __________ shape
indefinite, indefinite
solid to gas
sublimation
atomic mass (mass number) of an atom is 4. Number of protons equals 2. Number of neutrons are_____________
2
to separate element from compound, scientists ask this question
can it be separated by chemical means?
Electrons exist in probability clouds around the nucleus rather than fixed orbits.
Quantum Model