Atomic structure GapFill

All matter is made up of  ionschargesenergycellsatomsmolecules, which come in different types, called  atomselementsparticlesmetalsmoleculesreactants, represented using symbols which can be found on the  compound sequencegroup seriesInternetatomic modelreactivity listperiodic table. John Dalton developed his atomic theory, which stated that  atoms in an element are all uniqueatoms cannot be observedatoms can be created and destroyedall atoms are identicalatoms cannot be broken into smaller partsatoms are small, cube-shaped particles.

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  neutronsprotonsisotopesmoleculeselectronsions dotted around...
• Rutherford's model - the  magneticelectronicconnectiveelasticdirectionalnuclear model - based on the observations of  beta particlehalogenalpha particlemetallicradiationgamma particle scattering...
• Niels Bohr's model, where electrons orbit the  isotopesaltmetalsubatomic particleionnucleus...
• and James Chadwick's model, where neutrons are also in the nucleus

Different  omegaalphasubatomicinfraredmagneticultrasonic particles have different masses and charges. Protons (positive particles) and neutrons (neutral particles) have a mass of  0.511210-12, 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  saltsbondscompoundsionsprotonsisotopes.