physical properties

can be observed without changing a substance into another substance

boiling point, density, mass, volume

examples of physical properties

boiling point, density, mass, volume

chemical properties

can only be observed when a substance is changed into another substance

example of chemical properties

flammability, corrosiveness, reactivity with acid

intensive properties

independent of the amount of the substance that is present

examples of intensive properties

density, boiling point, color

extensive properties

dependent upon the amount of the substance present

example of extensive properties

mass, volume, energy

physical changes

changes in matter that do not change the composition of a substance

examples of physical changes

change of state, temperature, volume

chemical changes

changes that result in new substances

example of chemical changes

combustion, oxidation, decomposition

dalton's postulates

concept that matter is conserved and made up of unique elemental substances formed by atoms

who discovered electron by the cathode-ray tubes

jj thompson

who measured the electron by the oil drop experiment

robert millikan

Who discovered the radioactivity?

Becquerel and the Curies

Who discovered the nucleus protons by the gold-foil experiment

ernest rutherford

Who discovered neutrons

Chadwick

atomic number

number of electrons or protons

atomic mass

number of protons + neutrons

isotopes

same element, different number of neutrons

Group 1

alkai metal

Group 2

akaline earth metal

Group 6

chalcogens

group 7

halogens

group 8

noble gas

empirical formulas

give the lowest whole number of ratio of atoms of each element in a compound

molecular formulas

give the exact number of atoms of each element in a compound

formula weight

sum of the atomic weights for the atoms in a chemical formula

molecular weight

sum of the atomic weights of the atoms in a molecule

limiting reactants

reactant present in the smallest stoichiometric amount