Model of the atom GapFill

All matter is made up of  atomscellsenergyions, which come in different types, called  atomsparticleselementsreactants, represented using symbols which can be found on the  Internetperiodic tablecompound sequencereactivity list. When these react together,  mixturesbeta particlesatomscompounds are formed, which have formulae to show the  positionratiopercentageimportance of each element.  MixturesNeutronsElectronsPure 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  upside-down pineappledough ballplum puddingdoughnut model, where the atom is a ball of positive charge with electrons dotted around
• Rutherford's model - the  electronicnucleardirectionalconnective model - based on the observations of  alpha particlemetallicbeta particlegamma particle scattering
•  Neil ArmstrongIsaac NewtonNiels BohrMarie Curie's model, where electrons orbit the nucleus
•  Dmitri MendeleevJames DaltonCharles DarwinJames Chadwick's model, where neutrons are also in the nucleus

Different  subatomicinfraredmagneticalpha particles have different masses and charges. Protons (positive particles) and neutrons (neutral particles) have a mass of  -112110, 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  bondsprotonsisotopessalts.