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understand the Atom

Vocabulary for Understanding the Atom

atom smallest particle of an element that still represents that element
electron particle with one negative charge
nucleus center of the atom where protons and neutrons are located
proton particle with one positive charge
neutron neutral particle found in the nucleus
electron cloud part of the atom outside the nucleus that contains the electrons
atomic number the number of protons in an atom of an element
isotope an atom of the same element that have different numbers of neutrons
mass number is the sum of the number of protons and neutrons in an atom's nucleus
average atomic mass the average mass of the element's isotopes
radioactive elements that spontaneously emit radiation
nuclear decay a process that occurs when an unstable atomic nucleus changes into another more stable nucleus by emitting radiation
ion an atom that is no longer neutral because it has gained or lost electrons
Democritus said atoms are uncuttable, they are the smallest particle of matter, they are indivisible and not destructible
Dalton all matter is made of atoms, atoms can not be created or destroyed, all compounds are combinations of 2 or more atoms
JJ Thompson discovered the electron
Ernest Rutherford showed most of the mass of the atom is in the nucleus and the rest is empty space
Niels Bohr said electrons travel in energy levels around the nucleus
Chadwick added the addition of neutrons to the nucleus of the atom
quark smaller parts of the protons and neutrons
Created by: hallet