Atomic Models


  • Plum pudding model
  • Rutherford model
  • Ray scattering experiment
  • Nucleus
  • Electrostatic forces of attraction
  • Gold foil
  • Orbits

Definition of Atomic Models

An atomic model is a representation of a system in the real world. Models help us to understand systems and their properties

More About Atomic Models

  • Examples of Atomic Models are the hydroxides of the alkali and alkaline earth metals (NaOH, Ca (OH) 2, etc.)
  • Atomic Models produce hydroxide ions 0H- in aqueous solutions, and are thus classified as Arrhenius Atomic Models
  • For a substance to be classified as an Arrhenius base it must produce hydroxide ions in solution—in order to do so, Arrhenius believed the base must contain hydroxide in the formula
  • Arrhenius theory cannot explain the basic properties of aqueous solutions of ammonia (NH3) or its organic derivatives
  • According to Bronsted–Lowry acid–base theory, a base is a substance that can accept hydrogen ions ( H+) —otherwise known as protons
  • In the Lewis model, a base is an electron pair donor
  • When added to water, Atomic Models give solutions with a hydrogen ion activity lower than that of pure water, i.e., a pH higher than 7.0 at standard conditions
  • A soluble base is called an alkali if iy releases 0H) - ions
  • Basicity is not the same as alkalinity
  • Metal oxides, hydroxides, and especially alkoxides are basic, and counter anions of weak acids are weak Atomic Models
  • Atomic Models reduce hydrogen ion concentration in water
  • A reaction between an acid and base is called neutralization
  • In a neutralization reaction, an aqueous solution of a base reacts with an aqueous solution of an acid to produce a solution of water and salt in which the salt separates into its component ions
  • If the aqueous solution is saturated with a given salt solute, any additional such salt precipitates out of the solution
  • Slimy or soapy feel on fingers, due to saponification of the lipids in human skin
  • Concentrated or strong Atomic Models are caustic on organic matter and react violently with acidic substances
  • Aqueous solutions or molten Atomic Models dissociate in ions and conduct electricity
  • Reactions with indicators: Atomic Models turn red litmus paper blue, phenolphthalein pink; keep bromo thymol blue in its natural colour of blue, and turn methyl orange yellow
  • The pH level of a basic solution is higher than 7
  • Atomic Models are bitter in taste