Everything is made from atoms, including you. Atoms are tiny particles that are far too small to see, even with a microscope. If people were the same size as atoms, the entire population of the world would fit into a box about a thousandth of a millimeter across. After watching all the following youtube videos you will be able to describe the atom and its structure! (Wait until the videos are loaded). You can make the video playing fullscreen, by clicking the small square that appears when you hover at the bottom right corner of the video.
[embedyt] https://www.youtube.com/embed?listType=playlist&list=PLDoryZSIouvT_UcJW2ULYk2K3MYOlzlQT&v=pNroKeV2fgk&layout=gallery[/embedyt]Here is more helpful information about an atom and its structure
An atom has a central nucleus. This is surrounded by electrons arranged in shells.
The nucleus is tiny compared to the atom as a whole:
- the radius of an atom is about 0.1 nm (1 × 10-10 m)
- the radius of a nucleus (1 × 10-14 m) is less than
of the radius of an atom
For comparison, the radius of a typical bacterium is 1 × 10-6 m and the radius of a human hair is about 1 × 10-4 m.
Subatomic particles
The nuclei of all atoms contain subatomic particles called protons. The nuclei of most atoms also contain neutrons.
The structure of a carbon atom, not drawn to scale
The masses of subatomic particles are very tiny. Instead of writing their actual masses in kilograms, we often use their relative masses. The relative mass of a proton is 1, and a particle with a relative mass smaller than 1 has less mass.
| Subatomic particle | Relative mass | Relative charge |
|---|---|---|
| Proton | 1 | +1 |
| Neutron | 1 | 0 |
| Electron | Very small | -1 |
The mass of an electron is very small compared to a proton or a neutron. Since the nucleus contains protons and neutrons, most of the mass of an atom is concentrated in its nucleus.
Protons and electrons have electrical charges that are equal and opposite.
