The Composition of the Nucleus
- You have learn in chemistry that in an atom, electrons move around a central core called the nucleus.
- The nucleus consists of protons and neutrons. It containing almost all the mass of the atom.
- The nucleus of an atom is very small compared to the size of the atom
- Protons and neutrons also known as nucleons.
Nuclide Notation
- Proton number is defined as the number of protons in a nucleus.
- Nucleon number is defined as the total number of protons and neutrons in a nucleus. It is also known as mass number.
- A nuclide is a type of atom with a particular proton and nucleon number.
- A nuclide can be represented by a nuclide notation that shows the symbol of element, proton number and nucleon number.
- Figure below shows the nuclide notation of a nitrogen.
Isotopes
- Isotopes are atoms of certain elements which have the same number of protons but different number of neutrons in the nucleus of the atoms.
- It can also be defined as atoms of certain elements with the same proton numbers but with different nucleon numbers.
- Isotopes have the same chemical properties but different physical properties.
- Table below shows the proton and nucleon number of the isotopes of hydrogen and oxygen.
| Element | Name | Symbol | Proton Number | Nucleon Number | Number of proton | Number of neutron |
| Hydrogen | Hydrogen |
1
|
1
|
1
|
0
| |
| Deuterium |
1
|
12
|
1
|
1
| ||
| Tritium |
1
|
23
|
1
|
2
| ||
| Oxygen | Oxygen-16 |
8
|
16
|
8
|
8
| |
| Oxygen-17 |
8
|
17
|
8
|
9
| ||
| Oxygen-18 |
8
|
18
|
8
|
10
| ||
