This question is about potassium and zinc - Edexcel - GCSE Chemistry - Question 5 - 2021 - Paper 1
Question 5
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°C
D 63... show full transcript
Worked Solution & Example Answer:This question is about potassium and zinc - Edexcel - GCSE Chemistry - Question 5 - 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 melting point of potassium is most likely to be 63°C. This is the only suitable option because potassium, being an alkali metal, has a low melting point. The other temperatures either indicate a solid state at room temperature or are too high.
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 (K) has the atomic number 19, which means it has 19 electrons. Its electronic configuration is 2.8.8.1. The outermost shell contains 1 electron, placing potassium in Group 1 of the periodic table. Additionally, it has 4 electron shells, indicating that it is in period 4.
Step 3
Describe the test to show that a gas is oxygen.
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Answer
To demonstrate that a gas is oxygen, a glowing splint can be used. If the splint relights upon exposure to the gas, it confirms the presence of oxygen.
Step 4
Write the electronic configurations for the ions in potassium oxide, K₂O.
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Answer
The electronic configuration of the potassium ion (K⁺) is 2.8. The oxide ion (O²⁻) has an electronic configuration of 2.8.
