Atomic structure GapFill

All matter is made up of  cellsionsmoleculeschargesatomsenergy, which come in different types, called  particlesreactantsmetalsatomsmoleculeselements, represented using symbols which can be found on the  group seriescompound sequenceInternetatomic modelperiodic tablereactivity list. John Dalton developed his atomic theory, which stated that  atoms are small, cube-shaped particlesall atoms are identicalatoms cannot be broken into smaller partsatoms cannot be observedatoms 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  moleculesneutronsionsprotonselectronsisotopes dotted around...
• Rutherford's model - the  magneticelasticconnectiveelectronicnucleardirectional model - based on the observations of  halogenradiationgamma particlebeta particlealpha particlemetallic scattering...
• Niels Bohr's model, where electrons orbit the  ionsubatomic particlenucleussaltisotopemetal...
• and James Chadwick's model, where neutrons are also in the nucleus

Different  alphasubatomicultrasonicinfraredmagneticomega particles have different masses and charges. Protons (positive particles) and neutrons (neutral particles) have a mass of  100.512-121, 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  bondsprotonsisotopesionssaltscompounds.