Structure of the atom
The typical size of atoms and small molecules is around 1 脳 10-10 m (0.1 nm). For example:
| diameter of a hydrogen atom, H | 1.0 脳 10-10 m |
| width of a hydrogen molecule, H2 | 2.9 脳 10-10 m |
| length of an H-H bond | 0.74 脳 10-10 m |
| diameter of a hydrogen atom, H |
| 1.0 脳 10-10 m |
| width of a hydrogen molecule, H2 |
| 2.9 脳 10-10 m |
| length of an H-H bond |
| 0.74 脳 10-10 m |
Nucleus and shells
An The smallest part of an element that can exist. consists of:
- a positively charged The central part of an atom. It contains protons and neutrons, and has most of the mass of the atom. The plural of nucleus is nuclei.
- surrounded by negatively charged Subatomic particle, with a negative charge and a negligible mass relative to protons and neutrons.
Compared to an atom as a whole:
- the radius of the nucleus is much smaller than the radius of the atom
- the nucleus contains almost all of the mass
Learn more on atomic structure in this podcast.
Listen to the full series on 91热爆 Sounds.
Subatomic particles
The Nuclei is the plural of nucleus. The nucleus is the central part of an atom. It contains protons and neutrons, and has most of the mass of the atom. of all atoms contain Objects found in atoms, including protons, neutrons and electrons. called Subatomic particle with a positive charge and a relative mass of 1. The relative charge of a proton is +1. and most also contain Uncharged subatomic particle, with a mass of 1 relative to a proton. The relative charge of a neutron is 0..
The The amount of matter an object contains. Mass is measured in kilograms (kg) or grams (g). of subatomic particles are very tiny. Instead of writing their actual masses in kilograms, we often use their The relative mass is the number of times heavier a particle is, compared to another.. The relative mass of a proton is 1, and a particle with a relative mass smaller than 1 has less mass.
Protons and electrons have opposite electrical An imbalance of electrons and protons in a material. An excess of electrons results in negative charge, a deficit of electrons results in positive charge..
| Subatomic particle | Relative mass | Relative charge |
| Proton | 1 | +1 |
| Neutron | 1 | 0 |
| Electron | 0.0005 | -1 |
| Subatomic particle | Proton |
|---|---|
| Relative mass | 1 |
| Relative charge | +1 |
| Subatomic particle | Neutron |
|---|---|
| Relative mass | 1 |
| Relative charge | 0 |
| Subatomic particle | Electron |
|---|---|
| Relative mass | 0.0005 |
| Relative charge | -1 |