Model of the atom GapFill

All matter is made up of atoms cells ions energy , which come in different types, called elements atoms particles reactants , represented using symbols which can be found on the Internet periodic table compound sequence reactivity list . When these react together, beta particles atoms compounds mixtures are formed, which have formulae to show the ratio percentage importance position of each element. Neutrons Electrons Mixtures Pure substances contain multiple elements or compounds, and can be reacted shaped separated melted using filtration, distillation, crystallisation and chromatography.

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

• the upside-down pineapple plum pudding doughnut dough ball model, where the atom is a ball of positive charge with electrons dotted around
• Rutherford's model - the electronic directional nuclear connective model - based on the observations of alpha particle beta particle metallic gamma particle scattering
• Niels Bohr Neil Armstrong Isaac Newton Marie Curie 's model, where electrons orbit the nucleus
• Dmitri Mendeleev James Chadwick James Dalton Charles Darwin 's model, where neutrons are also in the nucleus

Different subatomic infrared magnetic alpha particles have different masses and charges. Protons (positive particles) and neutrons (neutral particles) have a mass of 10 12 1 -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 bonds isotopes protons salts .