Atomic structure GapFill

All matter is made up of  cellschargesmoleculesionsatomsenergy, which come in different types, called  metalsatomsparticleselementsreactantsmolecules, represented using symbols which can be found on the  compound sequenceperiodic tablegroup seriesreactivity listatomic modelInternet. John Dalton developed his atomic theory, which stated that  atoms in an element are all uniqueatoms are small, cube-shaped particlesatoms can be created and destroyedatoms cannot be observedall atoms are identicalatoms 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  protonsneutronsionsmoleculeselectronsisotopes dotted around...
• Rutherford's model - the  electronicconnectivenuclearelasticdirectionalmagnetic model - based on the observations of  halogenradiationalpha particlebeta particlegamma particlemetallic scattering...
• Niels Bohr's model, where electrons orbit the  subatomic particleionsaltisotopemetalnucleus...
• and James Chadwick's model, where neutrons are also in the nucleus

Different  subatomicalphaomegamagneticinfraredultrasonic particles have different masses and charges. Protons (positive particles) and neutrons (neutral particles) have a mass of  0.521012-11, 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  compoundsbondsprotonssaltsisotopesions.