Atomic theory and nuclear chemistry

The first lesson in the unit was about the different atomic theories that had existed.

The first theory was Dalton's atomic theory which had 5 postulates

1. All elements are composed of atoms 
2. all atoms of a given element are identical
3. atoms of different elements are different
4. compounds consist of the atoms of different elements
5. atoms are indivisible and are not created or destroyed in a chemical reaction

The law of constant composition is also covered in this section of the unit which states that a compound always contains the same proportion by mass of the element of which it is composed

We learned how to calculate the percent composition of each component in a compound because of this law of constant composition

Another person we learned about was JJ Thomson who helped to create the chocolate chip model which he discovered by using a cathode ray to show atoms of any element emit particles with a negative charge

The last theory we learned was the modern theory developed by Rutherford and his gold foil experiment which proved the presence of a positively charged center in a atom, the nucleus