Page 50 - Chemistry_Form_2

Chemistry
for Secondary Schools

11. (a) Given the elements calcium, sulfur, chlorine, helium and neon, write
their:
(i) period numbers.

(ii) group numbers.
FOR ONLINE READING ONLY
(iii) atomic numbers.
(iv) number of electrons in their atoms.

(v) electronic configurations.
(b) Which of the above elements would you expect to have similar
properties? Give reasons.

12. During a science lesson, students added a small piece of sodium (Na)
into water and observed fizzing and heat. They repeated the same with
magnesium (Mg), and there was very little reaction. Using periodic
classification, explain why the reaction of sodium with water was vigorous
than that of magnesium.

13. Greenish Secondary School is building a simple application (App) that can
help Form Two students to identify if an element is a metal, non-metal, or

metalloid. What features of periodic classification should be included in the
App to help students make the correct decision?
14. A cook wants to buy a new cooking pot. The shopkeeper offers two options:

one made from aluminium and the other from a shiny, brittle material.
Based on periodic classification, which material is better for cooking pots
and why?

15. Form Two students are curious about the elements used in smartphones.
They found that lithium (Li) is used in the battery and silicon (Si) in the
screen. Based on their positions in the periodic table, explain why these
elements are suitable for their specific roles in smartphones.
16. Magnesium has the electronic configuration 2: 8: 2. Explain how this
configuration relates to its chemical reactivity and its position in the
periodic table.

17. Two elements, A and B, have electronic configurations 2: 8: 8 and 2: 8: 2,
respectively. Compare their positions in the periodic table and predict which
is more reactive. Give reasons for your answers.

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CHEMISTRY FORM TWO NEW 2025 DUMMY.indd 43