Ernest+Rutherford

__**Ernest Rutherford Biography:**__ Ernest Rutherford was a physicist who explained natural radioactivity, determined the structure of the atom. This changed one element into another by splitting the nucleus. Rutherford was born on August 30, 1871 in Nelson, New Zealand. He spent most of his professional career at McGill University in Montreal, Canada, Manchester University, and Cambridge University in the United Kingdom. He discovered and named alpha and beta radiation and he named the nucleus and the proton. He also predicted the existence of the neutron. Rutherford conducted the gold foil alpha particle experiment. With this he found that the atom was nuclear. For this discovery he was awarded the 1908 Nobel Prize in chemistry. Rutherford said that the simplest rays were obtained by hydrogen and they must be positively charged particles which he said were protons in 1914. In 1917 he put alpha particles through gas of nitrogen and he would see hydrogen coming up on the screen. He concluded that alpha particles were taking protons out of the nitrogen atoms. This was the first observation of nuclear reactions. __**Rutherford's Model:**__ The atom consisted of subatomic particles called protons and electrons, but it wasn’t clear how they were arranged. J.J Thomson suggested the plum pudding model. He thought that they were mixed throughout the atom. Rutherford tested Thomson’s hypothesis with his gold foil experiment. Rutherford stated that if Thomson’s model was correct then the mass of the atom would spread throughout the atom. If he shot high velocity alpha particles at the atom then there wouldn’t be much to deflect the alpha particles. He decided to test this with a thin film of gold atoms. As he thought most alpha particles went right through the gold foil. He decided to discard the plum model, and the only way the alpha particles could be deflected backwards was if most of the mass in an atom was in the nucleus. Rutherford came up with a new model of the atom. He developed the planetary model. It was all of the positive charge crammed inside a tiny, nucleus about ten thousand times smaller than the atom as a whole. This put all the protons in the nucleus and the electrons orbited around the nucleus. Rutherford felt that the atom was like a mini solar system. The electrons circle the nucleus in wide orbits just like planets orbit the sun.

__**Pros and Cons**__ The electrons do orbit the nucleus, but the model doesn't consist of neutrons. Protons are the only thing in the nucleus.

Worked on by Tori Raderstorf