the atoms of a given element are identical to each over
the atoms different elements are different from one another
during chemical reactions atomsrearrange to make differentsubstances
J.J Thompson
Plum pudding model
atoms are spheres of positive charge
electrons are dotted inside
The Geiger-Marsden experiment
Hans Geiger and Ernest Marsden tested the plum pudding model. They aimed beams of positively-charged particles at verythingold foil. These particles should have passedstraightthrough, according to the plum pudding model. However, many of them changeddirection. Ernest Rutherford explained these results in his ‘planetary model’:
atoms have a central, positively charged nucleus with most of the mass
electronsorbit the nucleus, like planets around a star