atoms and molecules Flashcards
elements come in 3 states of matter
solids - metals
liquids - Hg & Br2
gases - diatomic and inert monoatomic
allotropes
element that has different structural forms / connected in different ways
atoms sub atomic particles
protons
electrons
neutrons
atomic number
number of protons + number of electrons
mass number
number of protons + number of neutrons
protons
are positive with one unit of weight
electrons
are negative and have practically no weight
neutrons
are neutral with one unit of weight
atomic number
total number of protons
noble gases
helium
neon
argon
krypton
xenon
noble gas
this has a complete outer electronic shell
isotopes
atoms having the same value of protons but different values for neutrons
anions
have a minus sign
cations
have a positive sign
pure substances
elements and compounds
uncombined natural sources
silver Ag, gold Au, nitrogen N2, sulfur S
oxides
chromite FeCr2O4, magnetite FeO4, water H2O, carbons dioxide CO2
carbonates
limestone CaCO3, dolomite CaCO3MgCO3