Alpha decay
Alpha decay is when a helium nucleus is emitted from the isotope.
That means that 2 protons and 2 neutrons are emitted from the nucleus of the isotope.
Alpha decay equation
^A_Z X\,\,\rightarrow\,\,^{A-4}_{Z-2}Y\,\,+\,\,^4_2\alpha
Proton number change
When an atom emits alpha radiation, the proton number will decrease by 2.
That’s because it emits two protons, so now has 2 fewer protons.
Nucleon number change
When an atom emits alpha radiation, the nucleon number (mass number) decreases by 4.
This is because it loses two protons and two neutrons, so loses a total of 4 nucleons.
flashcards
| Question | Answer |
|---|---|
| What happens to the proton number when an atom emits alpha radiation? | It decreases by 2. |
| What happens to the nucleon (mass) number when an atom emits alpha radiation? | It decreases by 4. |
| What is emitted in alpha decay? | A helium nucleus (2 protons and 2 neutrons). |
| Write the general equation for alpha decay. |