Atomic structureIB MYP Sciences: Subtopic test

1. 1
   An aluminium atom has atomic number 13 and mass number 27. Aluminium is recycled in large quantities because it can be melted and reused many times.

   (a)

   How many neutrons are in one atom of this aluminium?

   [1 mark]

   • A13
   • B14
   • C27
   • D40

   (b)

   Which particle has a negligible mass and is found in shells around the nucleus?

   [1 mark]

   • AElectron
   • BProton
   • CNeutron
   • DIsotope

   (c)

   Explain why an aluminium atom has no overall electrical charge.

   [2 marks]

   Total for question 1: 4 marks

2. 2
   Table salt contains sodium ions. A sodium atom has atomic number 11 and mass number 23. When sodium reacts, each atom forms a sodium ion with a charge of +1.

   (a)

   Which statement describes an ion?

   [1 mark]

   • AAn atom with extra neutrons
   • BAn atom with no charge
   • CA group of protons in a nucleus
   • DA charged particle formed when an atom gains or loses electrons

   (b)

   How many electrons are in a sodium ion, Na⁺?

   [1 mark]

   • A11
   • B12
   • C10
   • D23

   (c)

   Explain how a sodium atom becomes a sodium ion with a charge of +1.

   [2 marks]

   Total for question 2: 4 marks

3. 3
   Carbon exists as several isotopes. The three most common are carbon-12, carbon-13 and carbon-14. All three have atomic number 6.

   (a)

   Describe how atoms of these three isotopes are similar and how they are different, in terms of protons, neutrons and electrons.

   [3 marks]

   (b)

   Chlorine also has isotopes. A sample of chlorine contains 75% chlorine-35 atoms and 25% chlorine-37 atoms. Calculate the relative atomic mass of the chlorine in this sample, and explain why the value is not a whole number.

   [4 marks]

   Total for question 3: 7 marks

4. 4
   A fluorine atom has atomic number 9 and mass number 19. Radioactive isotopes of some elements, such as fluorine-18 and iodine-131, are used in hospitals to diagnose and treat disease.

   (a)

   Describe the structure of a fluorine atom, giving the number, relative charge, relative mass and location of each type of subatomic particle, and explain why the atom is neutral.

   [6 marks]

   (b)

   Evaluate the use of radioactive isotopes in hospitals to diagnose and treat disease. Discuss the benefits and drawbacks for patients and for society, and reach a justified conclusion.

   [6 marks]

   Total for question 4: 12 marks

End of questions