C1.5-History Of the Atom Flashcards
What model did John dalton come up with in 1803?
The solid sphere model
What did the solid sphere model suggest?
RECOGNISED ATOMS OF A PARTICULAR ELEMENT DIFFER FROM OTHER ELEMENTS
What model did J.J Thomson come up with in 1904?
The plum pudding model
What did the plum pudding model suggest?
RECOGNISED ELECTRONS AS COMPONENTS OF ATOMS
What model did Ernest rutherford come up with in 1911?
The nuclear model
What did the nuclear model suggest?
Positive charge was localised in the nucleus of an atom
What was Ernest rutherford’s scattering experiment?
In the experiment, positively charged alpha particles were fired at thin gold foil. Most alpha particles went straight through the foil. But a few were scattered in different directions. This evidence led Rutherford to suggest a new model for the atom, called the nuclear model .
What was the name of the model Niels Bohr came up with in 1913?
Planetary model
What did the planetary model suggest ?
Electrons orbit the nucleus
What model did Erwin schrödinger come up with in 1926?
The quantum model
What did the Quantum model suggest?
Electrons move around the nucleus in clouds where their position is uncertain
What are the key differences between the plum-pudding and the nuclear model?
The main difference between the Thomson and Rutherford atomic models is that the Thomson model contains no information about the nucleus of an atom, whereas the Rutherford model does
explain how the alpha scattering experiment disprove the plum pudding model
Rutherford carried out an experiment where he fired alpha particles at gold foil and observed the scattering of the particles. Most alpha particles fired went straight through suggesting than an atom is mainly empty space. Some positively charged alpha particles were deflected through large angles by the positive charge, concentrated at the nucleus. A few alpha particles were reflected straight back by the dense positive nucleus. Hence, disproving the Plum Pudding model which suggested that the atom consisted of positive ‘dough’ with a lot of negative electrons stuck in it.
