Use the periodic table to help you answer the following question - Edexcel - GCSE Chemistry - Question 3 - 2017 - Paper 1
Question 3
Use the periodic table to help you answer the following question.
Which of these metals will form coloured cations?
Put a cross (✗) in the box next to your answer.
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Worked Solution & Example Answer:Use the periodic table to help you answer the following question - Edexcel - GCSE Chemistry - Question 3 - 2017 - Paper 1
Step 1
Which of these metals will form coloured cations?
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Answer
A gallium, Ga x
B chromium, Cr ✓
C strontium, Sr ✓
D sodium, Na ✓
Chromium, strontium, and sodium form coloured cations when dissolved in solution.
Step 2
Explain, in terms of the structure of their atoms, why caesium is more reactive than lithium.
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Answer
Caesium is more reactive than lithium because it has more electron shells, which means its outer electron is further from the nucleus. The increased distance weakens the electrostatic attraction between the nucleus and the outer electron, making it easier for caesium to lose this electron in reactions.
Step 3
Write the balanced equation for this reaction.
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Answer
The balanced equation for the reaction of potassium with water is:
2K+2H2O→2KOH+H2
Step 4
Which of these is the balanced equation for this reaction?
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Answer
The correct balanced equation is:
B Cl₂ + KBr → KCl + Br₂
Step 5
Explain why filament light bulbs were filled with argon rather than left with air inside them.
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Answer
Filament light bulbs were filled with argon rather than air because argon is an inert gas. It prevents the tungsten filament from oxidizing and burning out quickly. Air, which contains oxygen, would react with the hot filament and shorten its lifespan.
