The behavior of cathode rays in a glass tube containing gas at low pressure led scientists to conclude that rays are composed of
negative particles
The basic principles of atomic theory were first conceived by
Dalton
the las of multiple proportions is demonstrated by the compunds
CO and CO2
neutral atoms of the same element can differ in
mass number
Dalton's atomic theory helped to explain the law of conversation of mass because it stated that atoms
cannot be created or destroyed
millikan's experiments led to the determination
of approximate value of electron's mass
the discovery of the nucleus was a result of Rutherford's observation that a small percentage of the positively charged particles bombarding
we're deflected back toward the source
most of the volume of an atom is occupied by the
electrons
definite proportions
if a particular compound is composed of elements A and B, the ratio of the mass of B to the mass of A will always be the same.
Mole
the amount of a substance that contains a number of particles equal to the number of atoms in exactly 12g of carbon-12
electrons
any metal cathode used in a cathode-ray tube produces the same charged particles, all atoms included...............
the smallest particle of an element that retains the chemical properties of that element
atom
atoms of one element that have different masses are called
isotopes
the total number of protons and neutrons in the nucleus of an isotopes is called
mass
they short range attractive forces that hold the nuclear particles together are
nuclear forces