History of the Atom
Storyboard Text
- History of the Atom
- Timeline
- Democritus (460BC-370BC)
- Model of an atomos:
- Greetings from Greece, I have an idea! When divided, all matter reaches a point where it can't be divided anymore.
- John Dalton (~1803)
- Hello my name is John Dalton and here is my theory.
- Model:
- Dalton's Atomic Theory:- All elements are composed of atoms (which can't divide or be destroyed).-All atoms of the same elements are alike, but two elements don't share similar atoms- Atoms of different elements combine to form a compound -They have to be a whole number ratio
- The history of the atom begins around 400 B.C.E., with a Greek philosopher named Democritus.
- J.J. Thompson (Late 1800s)
- After experimenting with gas discharge tubes, I now know there is a negatively charged particle in the atom called an electron
- .........................................
- Model:
- Democritus thought of this theory by thinking about an apple. If you continuously cut an apple into smaller pieces, eventually you will reach a point where the apple can't be divided anymore. He called those pieces atomos.
- Lord Ernest Rutherford (1871-1937)
- Dalton used the experiments of other scientists during his time as evidence for this theory.
- Niels Bohr (Early 1900s)
- I now know the real model of an atom! All electrons orbit around the nucleus, and depending on the elctrons' energy level, they can also go up or down levels.
- ________________________ n=6________________________ n=5________________________ n=4________________________ n=3________________________ n=2________________________ n=1
- While experimenting with gas discharge tubes, Thompson noticed a movement within them. He called the movement cathode rays and observed them. The rays moved from the negative side of the tube toward the positive side because they were negatively charged.
- The gold foil experiment provided evidence for Rutherford's hypothesis. He used special equipment to shoot alpha particles at a thin sheet of gold foil. Some particles passed straight through the foil (meaning they didn't hit a particle), while some were deflected by hitting something positivve.
- Thanks to my gold foil experiment, I now know that atoms are mostly empty-space, and are made up of a small positive-charged nucleus.
- Model:
- Everyone knows that Bohr is right because those who try out his theory on Hydrogen, get the same results (of it being correct). However, each element has orbitals at different energies, so his formula only works for Hydrogen.
Over 30 Million Storyboards Created