matter is made of
atoms, daltons atomic theory
Elements are made of
only one kind of atom, daltons atomic theory
Atoms in one element differ from atoms of all other elements how?
atoms differ in properties, daltons theory
compounds consist of
atoms of two or more elements combined in a small whole number ratio, daltons theory
what happens to atoms during chemical changes
atoms are rearranged not destroyed nor created, daltons theory
Law of definite proportions LDP
(constant composition): all samples of a pure compound contain the same elements in the same proportion by mass
Law of multiple proportions
two elements react to form more than one compound in different ratios
Atomic mass unit (amu) based on?
most common isotope
Isotopes, Radioactivity experiments
Frederick Soddy
Electrons, Cathode ray tubes
JJ THompson
Neutrons, Gamma radiation experiments
James chadwick
Protons and nucleus, Alpha particle gold foil
Ernest Rutherford
Radioactivity experiments
Isotopes
Electrons
Cathode ray tubes
Neutrons
Gamma radiation experiments
Protons and nucleus
Alpha particle gold foil
anion
atom, negative charge, gains electron(s)
cation
atom, positive, loses electron(s)
Average mass?
sum of fractional abundance x isotopic mass
fractional abundance of each isotope?
average mass = (x mass1)+ [(1-x) mass2]
