Question

radioactive decay (aka transmutation)
name _____________ period___

1. define transmutation
2. why do some elements atoms decay?
3. define half - life
4. alpha decay

proton change
neutron change
atomic number change
mass number change

1. beta decay

proton change
neutron change
atomic number change
mass number change

1. gamma decay

proton change
neutron change
atomic number change
mass number change

1. during alpha decay what nucleons break free from the atoms nucleus? _______________
2. during beta decay _____________ is converted into ___________ & _____________.
3. during gamma decay what happens to the overall energy of the nucleus? _______________

identify the following nuclear decay equations as alpha, beta, or gamma.
1.
$ce{_{88}^{226}ra -> _{2}^{4}he + _{86}^{222}rn}$
circle one: alpha beta gamma
2.
$ce{_{20}^{47}ca -> _{-1}^{0}e + _{21}^{47}sc}$
circle one: alpha beta gamma
3.
$ce{_{84}^{214}po -> _{2}^{4}he + _{82}^{210}pb}$
circle one: alpha beta gamma
4.
$ce{_{64}^{148}gd -> gamma + _{64}^{148}gd}$
circle one: alpha beta gamma
5.
$ce{_{6}^{14}c -> _{-1}^{0}e + _{7}^{14}n}$
circle one: alpha beta gamma
6.
$ce{_{64}^{148}gd -> _{2}^{4}he + _{62}^{144}sm}$
circle one: alpha beta gamma

Explanation:

1. Transmutation describes the nuclear process that changes the identity of an atom.
2. Unstable nuclei decay to reach a more stable nuclear configuration.
3. Half-life is a core measure of radioactive decay rate.
4. Alpha decay emits a $^4_2\text{He}$ particle, reducing protons/neutrons by 2 each, atomic number by 2, mass number by 4.
5. Beta decay converts a neutron to a proton + electron, increasing protons/atomic number by 1, decreasing neutrons by 1, with no mass number change.
6. Gamma decay only releases energy (no particle emission), so nuclear properties remain unchanged.
7. Alpha decay's emitted particle is a helium nucleus.
8. Beta decay's core reaction is neutron → proton + electron.
9. Gamma decay releases excess nuclear energy, lowering the nucleus's energy state.

10.

1. Equation emits $^4_2\text{He}$, the marker of alpha decay.
2. Equation emits $^0_{-1}e$, the marker of beta decay.
3. Equation emits $^4_2\text{He}$, the marker of alpha decay.
4. Equation emits $\gamma$ (gamma radiation), the marker of gamma decay.
5. Equation emits $^0_{-1}e$, the marker of beta decay.
6. Equation emits $^4_2\text{He}$, the marker of alpha decay.

Answer:

1. Transmutation is the conversion of one chemical element or isotope into another.
2. Their nuclei are unstable (have too many protons/neutrons, or excess energy).
3. Half-life is the time required for half of a radioactive sample's atoms to decay.
4. Alpha Decay:

• Proton change: Decreases by 2
• Neutron change: Decreases by 2
• Atomic Number change: Decreases by 2
• Mass Number change: Decreases by 4

1. Beta Decay:

• Proton change: Increases by 1
• Neutron change: Decreases by 1
• Atomic Number change: Increases by 1
• Mass Number change: No change

1. Gamma Decay:

• Proton change: No change
• Neutron change: No change
• Atomic Number change: No change
• Mass Number change: No change

1. A helium nucleus (2 protons and 2 neutrons, an alpha particle)
2. A neutron; a proton; an electron (beta particle)
3. The overall energy of the nucleus decreases (it releases excess energy as gamma radiation).
4. Nuclear Decay Identification:
5. alpha
6. beta
7. alpha
8. gamma
9. beta
10. alpha