atomic model timeline part1.pptx physical science

atoms

1. Atomic model: John Dalton Matter is made of small indivisible atoms. Atoms can’t be subdivided, created or destroyed. 2.1 Atoms of the same element have the same property. 2.2 Atoms of different elements have different properties. 3. Atoms of different elements can form compounds.

2. Plum-pudding model: J.J. Thomson An atom is electrically neutral. It has no charge. In an atom, both positive charges and negative charges are equal. An atom is made out of a sphere of positive charges with negatively charged electron embedded in it.

3. Nuclear model: Ernest Rutherford Atoms are mostly empty space. Most of the mass is concentrated in the center of atom. This tiny, dense, positively charged core called a nucleus. Electrons are located outside the nucleus.