Isotopes
Atoms which have the same number of protons (so they are atoms of the same element) but they have a different number of neutrons (so they have a different mass number). are atoms of an An element is a substance that consists of only one type of atom and it cannot be broken down into anything simpler by chemical means. with the same atomic number, but a different mass number. They have a different number of neutrons.
Chlorine exists as two common isotopes.
The table below shows the number of Objects found in atoms, including protons, neutrons and electrons. in atoms of the two isotopes of chlorine.
| Atom | Atomic Number | Mass number | Number of protons | Number of neutrons | Number of electrons |
| 35Cl | 17 | 35 | 17 | (35 – 17) = 18 | 17 |
| 37Cl | 17 | 37 | 17 | (37 – 17) = 20 | 17 |
| Atom | 35Cl |
|---|---|
| Atomic Number | 17 |
| Mass number | 35 |
| Number of protons | 17 |
| Number of neutrons | (35 – 17) = 18 |
| Number of electrons | 17 |
| Atom | 37Cl |
|---|---|
| Atomic Number | 17 |
| Mass number | 37 |
| Number of protons | 17 |
| Number of neutrons | (37 – 17) = 20 |
| Number of electrons | 17 |
