Model of the atom GapFill

All matter is made up of  energycellsionsatoms, which come in different types, called  particlesreactantsatomselements, represented using symbols which can be found on the  compound sequencereactivity listInternetperiodic table. When these react together,  atomsbeta particlesmixturescompounds are formed, which have formulae to show the  ratiopercentagepositionimportance of each element.  ElectronsMixturesNeutronsPure substances contain multiple elements or compounds, and can be  shapedseparatedreactedmelted using filtration, distillation, crystallisation and chromatography.

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

• the  plum puddingdoughnutupside-down pineappledough ball model, where the atom is a ball of positive charge with electrons dotted around
• Rutherford's model - the  connectivedirectionalelectronicnuclear model - based on the observations of  gamma particlealpha particlebeta particlemetallic scattering
•  Neil ArmstrongMarie CurieIsaac NewtonNiels Bohr's model, where electrons orbit the nucleus
•  Dmitri MendeleevJames DaltonCharles DarwinJames Chadwick's model, where neutrons are also in the nucleus

Different  alphamagneticsubatomicinfrared particles have different masses and charges. Protons (positive particles) and neutrons (neutral particles) have a mass of  10112-1, 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  protonssaltsbondsisotopes.