Science 9 · Unit 2: Properties of materials · Cambridge Lower Secondary Science Stage 9

Questions

1. 1. Helium, neon and argon are in Group 8, the noble gases. Why do they hardly react at all?

   • They are metals.
   • Their outer electron shells are full.
   • They have only one outer electron.
   • Their atoms have no electrons.
   Check

2. 2. Noble gas boiling points: helium −269 °C, neon −246 °C, argon −186 °C. What is the trend going down Group 8?

   • The noble gases have no boiling point.
   • The boiling point stays the same.
   • The boiling point increases.
   • The boiling point decreases.
   Check

3. 3. Match each group with its trend going down the group.

   • Group 1
   • Group 7
   • Group 8

   • less reactive and higher melting points
   • unreactive, with rising boiling points
   • more reactive and lower melting points
   Check

4. 4. Lithium, sodium and potassium are in Group 1. What happens to the number of protons as you go down the group?

   • It goes up and then down.
   • It stays the same.
   • It decreases.
   • It increases.
   Check

5. 5. What can you say about the mass number of lithium (7), sodium (23) and potassium (39) as you look down Group 1?

   • It goes up and then down.
   • It decreases.
   • It increases.
   • It stays the same.
   Check

6. 6. A sodium atom has 11 protons and 12 neutrons. What is its mass number?

   • 12
   • 23
   • 1
   • 11
   Check

7. 7. A sodium atom has 11 protons and mass number 23. How many neutrons does it have?

   • 11
   • 34
   • 12
   • 23
   Check

8. 8. Sodium has atomic number 11. What is its electronic structure?

   • 2,8,1
   • 2,9
   • 11
   • 2,8,2
   Check

9. 9. A potassium atom has 19 protons and mass number 39. How many neutrons does it have?

   • 20
   • 58
   • 39
   • 19
   Check

10. 10. What is the electronic structure of potassium (19 electrons)?

    • 2,8,8,2
    • 2,17
    • 2,8,9
    • 2,8,8,1
    Check

11. 11. What is the same about the atoms of lithium (2,1), sodium (2,8,1) and potassium (2,8,8,1)?

    • They all have one electron in the outer shell.
    • They all have the same number of shells.
    • They all have a full outer shell.
    • They all have the same number of protons.
    Check

12. 12. Which is a difference between a lithium atom and a potassium atom?

    • Potassium has fewer protons.
    • Lithium has more outer electrons.
    • Lithium's atom is bigger.
    • Potassium has more shells of electrons, so its atom is bigger.
    Check

13. 13. What is a group in the Periodic Table?

    • a horizontal row of elements
    • a vertical column of elements
    • all the metals
    • all the gases
    Check

14. 📖 This question is about a text that students read in the app.

    14. As the atomic numbers in Group 7 increase, what happens to the melting and boiling points?

    • Both decrease.
    • Melting points increase but boiling points decrease.
    • Both increase.
    • They stay the same.
    Check

15. 📖 This question is about a text that students read in the app.

    15. Iodine is the fourth element in Group 7. Would you expect its melting point to be higher or lower than bromine's, and what state would iodine be at room temperature?

    • It melts above −7 °C, so it is a solid at room temperature.
    • It melts below −7 °C, so it is a liquid at room temperature.
    • It has the same melting point as bromine.
    • It melts below −7 °C, so it is a gas at room temperature.
    Check

16. 📖 This question is about a text that students read in the app.

    16. Would you expect iodine to have a higher or lower boiling point than astatine?

    • higher
    • lower
    Check

17. 📖 This question is about a text that students read in the app.

    17. Would you expect astatine to be more or less reactive than iodine?

    • more reactive
    • less reactive
    Check

18. 📖 This question is about a text that students read in the app.

    18. Which element in Group 7 is the most reactive?

    • bromine
    • astatine
    • fluorine
    • iodine
    Check

19. 📖 This question is about a text that students read in the app.

    19. As the atomic numbers in Group 1 increase, what happens to the melting point?

    • There is no pattern.
    • The melting point stays the same.
    • The melting point decreases.
    • The melting point increases.
    Check

20. 📖 This question is about a text that students read in the app.

    20. Compare the trends in boiling points in Group 1 and Group 7.

    • They increase in both groups.
    • They decrease in both groups.
    • In Group 1 they increase; in Group 7 they decrease.
    • In Group 1 they decrease; in Group 7 they increase.
    Check