Dalton's Atomic Theory
This is a picture of what Dalton believed
the atom to look like. As you can see, it is
a sphere, and it is not very complex.
2. All atoms of the same element share the same properties, or characteristics, the most important being the atomic mass of the atom. For example, any atom of Carbon has an atomic mass of12.01.
3. Elements can become compounds, which are created when two or more atoms of different elements combine. When this happens, the properties of each atom change, such as the number of electrons, in order to be able to be combined with the other element.
This is a picture of a compound. As you can see,
there are two "white" atoms combined with one "red" atom.
4. Chemical reactions are changes in atoms that occur when atoms are rearranged, and not created or destroyed. This shows that an element can't be transformed into another atom, and matter can't be produced or destroyed.
Here is an example of a chemical reaction.
In this picture, four Hydrogen atoms and two
Oxygen atoms are rearranged to produce two
water molecules (two hydrogen, one oxygen)
These two pictures (above and below) show Dalton's element symbols. Dalton created a symbol composed of a circle containing a different design for each element. However, scientists decided that these symbols were irrelevent, because they didn't accurately show the structure of the element.
For another explanation of Dalton's Atomic Theory, here's a link to a video that visually explains it - http://videos.howstuffworks.com/hsw/23467-atomic-structure-the-dalton-model-of-the-atom-video.htm