Model of the atom GapFill

All matter is made up of  cellsatomsionsenergy, which come in different types, called  atomsreactantsparticleselements, represented using symbols which can be found on the  Internetperiodic tablereactivity listcompound sequence. When these react together,  compoundsatomsmixturesbeta particles are formed, which have formulae to show the  ratiopercentagepositionimportance of each element.  Pure substancesNeutronsMixturesElectrons contain multiple elements or compounds, and can be  separatedshapedreactedmelted using filtration, distillation, crystallisation and chromatography.

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

• the  doughnutdough ballplum puddingupside-down pineapple model, where the atom is a ball of positive charge with electrons dotted around
• Rutherford's model - the  electronicconnectivedirectionalnuclear model - based on the observations of  beta particlegamma particlemetallicalpha particle scattering
•  Marie CurieNeil ArmstrongNiels BohrIsaac Newton's model, where electrons orbit the nucleus
•  Charles DarwinJames DaltonJames ChadwickDmitri Mendeleev's model, where neutrons are also in the nucleus

Different  subatomicinfraredalphamagnetic particles have different masses and charges. Protons (positive particles) and neutrons (neutral particles) have a mass of  10121-1, 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  saltsisotopesbondsprotons.