A different nucleus can be formed by bombarding a stable nucleus with an energetic α-particle.

Question 14

A different nucleus can be formed by bombarding a stable nucleus with an energetic α-particle.

²³₁₁Na is bombarded with an energetic α-particle.

What could be the products of this nuclear reaction?

A ²⁵₁₀Ne + neutron

B ²⁵₁₁Na + proton

C ²⁶₁₂Mg + β

D ²⁷₁₃Al + γ

Reference: Past Exam Paper – November 2012 Paper 12 Q40

Solution:

Answer: D.

An α-particle is a ⁴₂He nucleus.

For any nuclear reaction, the proton number and the nucleon number should be conserved. That is, the proton number and nucleon number of the reactants should be equal to that of the products.

²³₁₁Na   +   ⁴₂He           - - - >

Proton number of reactants = 11 + 2 = 13

Nucleon number of reactants = 23 + 4 = 27

Consider choice A: (A neutron is ¹₀n)

Proton number = 10 + 0 = 10 [not equal]

Nucleon number = 25 + 1 = 26 [not equal]

Consider choice B: (A proton is ¹₁p)

Proton number = 11 + 1 = 11 [not equal]

Nucleon number = 25 + 1 = 26 [not equal]

Consider choice C: (A beta particle is ⁰_-1β)

Proton number = 12 + -1 = 11 [not equal]

Nucleon number = 26 + 0 = 26 [not equal]

Consider choice D: (A gamma ray is ⁰₀γ)

Proton number = 13 + 0 = 13 [equal]

Nucleon number = 27 + 0 = 27 [equal]