This question is about Group 1 elements - AQA - GCSE Chemistry - Question 4 - 2021 - Paper 1
Question 4
This question is about Group 1 elements.
Give two observations you could make when a small piece of potassium is added to water.
1
2
Complete the equation for th... show full transcript
Worked Solution & Example Answer:This question is about Group 1 elements - AQA - GCSE Chemistry - Question 4 - 2021 - Paper 1
Step 1
Give two observations you could make when a small piece of potassium is added to water.
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Answer
Potassium floats on the surface of the water.
The potassium melts and moves around, producing a lilac flame and fizzing.
Step 2
Complete the equation for the reaction of potassium with water.
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Answer
K + 2H2O → 2KOH + H2
Step 3
Explain why the reactivity of elements changes going down Group 1.
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Answer
Reactivity increases going down the group because the outer electron is further from the nucleus; therefore, there is less attraction between the nucleus and the outer electron. This results in the atom losing an electron more easily.
Step 4
Draw a dot and cross diagram to show what happens when atoms of sodium and oxygen react to produce sodium oxide.
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Answer
The dot and cross diagram shows two sodium atoms donating their electrons to one oxygen atom. The result is two sodium ions, each with a +1 charge, and one oxide ion with a -2 charge.
Step 5
Why is oxygen described as being reduced in the reaction between sodium and oxygen?
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Answer
Oxygen gains electrons during the reaction.
Step 6
Explain why sodium oxide has a high melting point.
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Answer
Sodium oxide has a giant ionic structure, held together by strong electrostatic forces of attraction between oppositely charged ions. Thus, large amounts of energy are required to break these bonds and separate the ions.
