S1.2.2 – Isotopes
📌 What are isotopes?
- Isotopes are alternate forms of atoms that have varied number of neutrons in their nucleus
- The number of protons and electrons remain the same (thus the charge/proton number does not change) but the mass varies due to the varied number of neutrons
- The stability of isotopes depends on the number of protons and neutrons in the nucleus. If there are too many or too few neutrons, the isotope is unstable and can become radioactive. They behave the same way chemically as other isotopes.
- The average relative mass of isotopes can be calculated by multiplying the abundance of each isotope with it’s mass number and averaging this value
Example calculation
If we have Cl35and Cl37 with 78% and 22% abundance then :
[(35 x 78) + (37 x 22)]/(78+22) = 35.44
Therefore the relative mass is 35.44 for Cl atoms