ION – is an atom that is no longer neutral because it has gained or lost electron
NUCLEAR DECAY – is the process that occurs when an unstable atomic nucleus changes into another
more stable nucleus by emitting radiation
RADIOACTIVE – elements that spontaneously emit raditaion
AVERAGE ATOMIC MASS – is the average mass of the elements isotopes, weighted according to the
abundance of each isotopes
MASS NUMBER – is the sum of the number of protonsand neutron
ISOTOPES – are atoms in the same element that have different numbers of neutrons
ATOMIC NUMBER – the number or protons in an atom of an element
GAMMA DECAY – no change in protons (gamma rays)
BETA DECAY – one fewer neutron and one more proton
ALPHA DECAY – two fewer protons and two fewer neutrons
ELECTRON CLOUD – current explanation of where electrons might be found in the atom
ALPHA PARTICLE – used by Rutherford in his experiment made of two protons and two neutrons
BOHR – developed the model of the atom in which elements orbit the nucleus in energy levels
ELEMENT – building blocks of matter represented by a symbol
ENERGY LEVELS – the paths in which electrons circle the nucleus according to the Bohr model
NUCLEUS – the tiny positive core of an atom contains protons and neutrons
ATOM – the smallest particle of an element that has the properties of that element
THOMPSON – proposed the plum-pudding model of the model of the atom; discovered the electron
CHADWICK – discovered the neutron
NEUTRON – the neutral particle that circles the nucleus
PROTON – positively charge particle in the nucleus of an atom
ELECTRON – the negatively charged particle that circles the nucleus
DALTON – English schoolteacher who proposed the atomic theory model of matter
QUARK – small particle that make up protons and neutrons
RUTHERFORD – discovere the nucleus using his gold foil experiment
DEMOCRITUS – Greek philosopher who made a mental model of the atom