The Composition of the Nucleus
- You have learned in chemistry that in an atom, electrons move around a central core called the nucleus.
- The nucleus consists of protons and neutrons. It contains 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 are known as nucleons.
- 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 the 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 the element, proton number and nucleon number.
- The figure below shows the nuclide notation of nitrogen.
- 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.
- The table below shows the proton and nucleon number of the isotopes of hydrogen and oxygen.
|Number of proton
|Number of neutron