Sodium-24 and sodium-23 are two of the isotopes of sodium. Sodium-24 is a radioactive isotope that emits beta-particles and gamma-rays as it decays.

1. (a)(i)The nuclide notation for the isotope sodium-24 is ²⁴₁₁Na. Describe the composition and structure of a neutral atom of sodium-24.[3]
2. (a)(ii)State how the composition of a nucleus of sodium-24 differs from the composition of a nucleus of sodium-23.[1]
3. (b)(i)A nucleus of sodium-24 decays. It emits a beta-particle and produces a nucleus of an isotope of magnesium (Mg). State the name of the particle that is identical to a beta-particle.[1]
4. (b)(ii)Complete the nuclide equation for the emission of a beta-particle (β) by sodium-24. ²⁴₁₁Na → ẞ + Mg[3]
5. (c)When it decays, sodium-24 also emits gamma-rays. State what gamma-rays are.[2]
6. (d)Fig. 8.1 shows a beam of beta-particles and a beam of gamma-rays entering the electric field between two oppositely charged plates. [Figure 8.1]
7. (d)(i)On Fig. 8.1, draw the path of the beta-particles in the electric field between the charged plates.[1]
8. (d)(ii)On Fig. 8.1, draw the path of the gamma-rays in the electric field between the charged plates.[1]
9. (d)(iii)Explain why the path taken by the beta-particles differs from that taken by the gamma-rays.[1]
10. (e)Sodium-24 is sometimes used in diagnosing medical conditions. The half-life of sodium-24 is 15 hours. Explain one reason why a half-life of 15 hours makes the isotope suitable for use in the human body.[2]

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