This question is about potassium and zinc - Edexcel - GCSE Chemistry Combined Science - Question 3 - 2021 - Paper 1
Question 3
This question is about potassium and zinc.
(a) Which of the following temperatures is most likely to be the melting point of potassium?
☐ A -63°C
☐ B 6.3°C
☐ C 63°... show full transcript
Worked Solution & Example Answer:This question is about potassium and zinc - Edexcel - GCSE Chemistry Combined Science - Question 3 - 2021 - Paper 1
Step 1
Which of the following temperatures is most likely to be the melting point of potassium?
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Answer
The correct answer is C 63°C. Potassium is an alkali metal, and alkali metals typically have low melting points. Options A and B would indicate states (gas or liquid) that potassium could not possess at room temperature.
Step 2
Explain how the electronic configuration of an atom of potassium is related to its position in the periodic table.
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Answer
Potassium is located in Group 1 of the periodic table, which contains alkali metals. Its electronic configuration is 1s² 2s² 2p⁶ 3s¹. The single electron in the outermost shell (3s) determines its chemical reactivity and position in the table. Elements in the same group exhibit similar properties due to their similar valence electron configurations.
Step 3
Describe the test to show that a gas is oxygen.
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Answer
To test for oxygen, a glowing splint can be introduced into a test tube containing the gas. If the splint reignites or bursts into flames, this indicates the presence of oxygen.
Step 4
Write the electronic configurations for the ions in potassium oxide, K2O.
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Answer
In potassium oxide, K2O, potassium ions (K⁺) have the electronic configuration 1s² 2s² 2p⁶ (the loss of one 3s electron), while oxide ions (O²⁻) have the configuration 1s² 2s² 2p⁶ (gaining two electrons).
