Model of the atom GapFill

All matter is made up of  energyionscellsatoms, which come in different types, called  reactantselementsparticlesatoms, represented using symbols which can be found on the  reactivity listInternetcompound sequenceperiodic table. When these react together,  compoundsatomsbeta particlesmixtures are formed, which have formulae to show the  positionpercentageratioimportance of each element.  MixturesElectronsNeutronsPure substances contain multiple elements or compounds, and can be  shapedreactedmeltedseparated using filtration, distillation, crystallisation and chromatography.

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

• the  doughnutdough ballupside-down pineappleplum pudding model, where the atom is a ball of positive charge with electrons dotted around
• Rutherford's model - the  nucleardirectionalconnectiveelectronic model - based on the observations of  beta particlemetallicalpha particlegamma particle scattering
•  Isaac NewtonNiels BohrMarie CurieNeil Armstrong's model, where electrons orbit the nucleus
•  Dmitri MendeleevJames DaltonJames ChadwickCharles Darwin's model, where neutrons are also in the nucleus

Different  alphainfraredmagneticsubatomic particles have different masses and charges. Protons (positive particles) and neutrons (neutral particles) have a mass of  10-1121, 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  isotopessaltsbondsprotons.