1. CHEMISTRY DEPARTMENT WAID ACADEMY Radioactivity

2. Radioactive calcium would differ from ordinary (non-radioactive) calcium in its 1.atomic mass. 2.chemical properties. 3.atomic number. 4.electron arrangement. 20

3. What is the result of an atom losing a beta-particle? 25 1.Atomic number unchanged, mass number increased by 1. 2.Atomic number decreased by 2, mass number decreased by 4. 3.Atomic number increases by 1, mass number unchanged. 4.Atomic number decreased by 1, mass number unchanged.

4. The process shown below represents 25 1.nuclear fission. 2.nuclear fusion. 3.proton capture. 4.beta emission.

5. Beta-particles emitted by certain radioactive atoms are 25 1.electrons from the nucleus. 2.electrons from the outer electron energy level. 3.particles consisting of 2 protons and 2 neutrons. 4.electromagnetic radiation of very high energy.

6. Plants take in radon with water through their roots. Compared with radon in the water, the half-life of the radon in the plant cells will be 25 1.shorter. 2.longer. 3.dependent on the size of the plant. 4.the same.

7. The half-life of the isotope 14 C is 5.5 x 10 3 years. What fraction of the original 14 C atoms will be present after 2.2 x 10 4 years? 25 1.0.5 2.0.25 3.0.125 4.0.0625

8. A radioactive atom of a Group 5 element emits one beta-particle. The decay product will be an atom of an element in 25 1.Group 4 2.Group 5 3.Group 6 4.Group 7

9. The stability of the nucleus of an ion depends on the ratio of 25 1.neutrons : protons 2.mass : charge 3.neutrons : electrons 4.protons : electrons

10. Which of the following has an electrical charge? 25 1.X-rays. 2.alpha-particles. 3.Neutrons. 4.gamma-rays.

11. The chart below was obtained from an 8-day old sample of an alpha-emitting radioisotope. What is the half-life of the radioisotope? 1.2 days 2.4 days 3.8 days 4.12 days 25