Atomic structure GapFill

All matter is made up of    ionsenergychargesatoms, which come in different types, called    reactantsatomsmoleculeselements, represented using symbols which can be found on the    Internetperiodic tablegroup seriesreactivity list. John Dalton developed his atomic theory, which stated that    all atoms are identicalatoms cannot be observedatoms can be created and destroyedatoms cannot be broken into smaller parts.

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    electronsmoleculesneutronsions dotted around...
• Rutherford's model - the    electronicconnectiveelasticnuclear model - based on the observations of    alpha particlehalogenmetallicbeta particle scattering...
• Niels Bohr's model, where electrons orbit the    ionsaltisotopenucleus...
• and James Chadwick's model, where neutrons are also in the nucleus

Different    omegasubatomicultrasonicalpha particles have different masses and charges. Protons (positive particles) and neutrons (neutral particles) have a mass of    0.512-11, 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    protonsionsisotopescompounds.