Atomic structure GapFill

All matter is made up of  moleculescellschargesatomsionsenergy, which come in different types, called  atomsmoleculesreactantselementsparticlesmetals, represented using symbols which can be found on the  group seriesreactivity listcompound sequenceInternetatomic modelperiodic table. John Dalton developed his atomic theory, which stated that  all atoms are identicalatoms are small, cube-shaped particlesatoms cannot be observedatoms cannot be broken into smaller partsatoms can be created and destroyedatoms in an element are all unique.

Over time, different scientists have developed new models of the atom. These include:

• the plum pudding model, where the atom is a ball of positive charge with  neutronsprotonsionselectronsmoleculesisotopes dotted around...
• Rutherford's model - the  connectivedirectionalelectronicelasticnuclearmagnetic model - based on the observations of  alpha particlegamma particlemetallicbeta particleradiationhalogen scattering...
• Niels Bohr's model, where electrons orbit the  ionsaltisotopesubatomic particlemetalnucleus...
• and James Chadwick's model, where neutrons are also in the nucleus

Different  infraredsubatomicultrasonicalphaomegamagnetic particles have different masses and charges. Protons (positive particles) and neutrons (neutral particles) have a mass of  110120.52-1, and electrons (negative particles) have a very small mass. The relative atomic mass of an atom is the weighted average mass of all of the element's  bondsionscompoundssaltsprotonsisotopes.