What is an atom? An atom is the smallest particle of matter. It cannot be divided chemically.
An atom is very small. How small? Consider the following examples.
- A sheet of paper is about a million atoms thick.
- A drop of water can contain as many as 10 sextillion atoms.
- The diameter of the period at the end of this sentence is the length of at least 50 trillion atoms lined up in a row.
Check out this great site, it shows exactly how small an atom really is.
http://learn.genetics.utah.edu/content/begin/scale/
Rutherford's atomic modelIn this model, a small and dense nucleus contains the entire positive charge of the atom, while the eletrons, lightweight and negatively charged, are scattered randomly in a large space around the nucleus.
Rutherford-Bohr atomic modelThis model consists of a very small nucleus surrounded by electrons moving a series of orbits.
Simplified atomic modelResearch by Chadwick, in 1932, led to the addition of the neutron to the Rutherford-Bohr model.
An electron is one of the particles that make up an atom. It is negatively charged.
Cathode rays are identical regardless of the metal used to make the cathode. Thomson concluded that they are therefore common to all elements.
The proton is one of the particles that make up an atom. It is found in the nucleus and carries a positive charge.
I really like your blog. It is clear, colourful, and easy to follow. You have a lot of diagrams, which is great for readers who are visual.
ReplyDeleteOne pointer: make your font size a little bigger. Also your link to "the size of an atom" is not working. Fix it so that the hyperlink opens up in a new window.