1 / 7

Models of the Atom

Models of the Atom. Ancient Greeks: All matter is made up of atoms. These are indivisible. Different substances are made up of different types of atoms A homogeneous piece of matter is made up of all the same type of atom. Models of the Atom. Dalton (early 1800’s)

bradley-david
Download Presentation

Models of the Atom

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Models of the Atom Ancient Greeks: All matter is made up of atoms. These are indivisible. Different substances are made up of different types of atoms A homogeneous piece of matter is made up of all the same type of atom

  2. Models of the Atom Dalton (early 1800’s) All matter is made up of a great number of extremely small indivisible particles called atoms All atoms of one element are identical Atoms of different elements are different When a compound is formed, the compound atom is made up of fixed whole numbers of atoms of the constituent elements.

  3. Thompson (Plum Pudding Model) 1897 – Discovered the electron, a very small negatively charged particle Theory: Atoms consist of a sphere of uniformly distributed positive charge with electrons embedded like plums in a pudding Models of the Atom

  4. Models of the Atom α particle Problems with Thomson’s Model: Predicts that the positively charged α particle will pass straight through as it is more massive than an electron and it won’t encounter any accumulated positive charge

  5. Models of the Atom Rutherford’s experiment showed that most α particles pass straight through gold foil some were deflected through large angles very small number rebounded straight back Rutherford’s experiment showed the atom must be Mainly empty space Regions of high concentration of positive charge

  6. Models of the Atom Rutherford: Small central positively charged nucleus Surrounded by electrons in circular orbits

  7. Models of the Atom Problems with Rutherford’s model: To stay in orbit, electrons must accelerate Accelerating charges are known to radiate energy in the form of electromagnetic radiation (eg light) So the electrons should: Radiate energy Spiral towards the nucleus causing the atom to collapse. This does not happen

More Related