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2018 O Level Chem P1 Q26 — Periodic Table / Reactivity Trends Solution

Periodic Table / Reactivity Trends 2018 O Level Pure Chemistry · Paper 1 · Q26

Question

Part of the Periodic Table is shown. Which of the elements W, X, Y and Z would react together least violently? Question diagram

Question diagram

AW and X
BW and Z
CX and Y
DY and Z

Correct answer: B

Video Solution

Explanation

Answer: B (W and Z). The diagram places W and Y in Group 1 (W above Y) and X and Z in Group 17 (X above Z).

Going down Group 1, reactivity increases (the outer electron is lost more easily), so W is the less reactive alkali metal. Going down Group 17, reactivity decreases, so Z is the less reactive halogen.

The least violent reaction is between the least reactive metal and the least reactive non-metal, which is W and Z. The most violent would be Y and X. Answer B.

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