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.
A lilac flame appears as potassium reacts.
Step 2
Complete the equation for the reaction of potassium with water.
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Answer
The balanced equation is:
ightarrow 2KOH + H_2$$
Step 3
Explain why the reactivity of elements changes going down Group 1.
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Answer
Reactivity increases down Group 1 because the outer electron is further from the nucleus. This distance results in less attraction between the nucleus and the outer electron, making it easier for the atom to lose this electron.
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 each donate one electron to one oxygen atom.
This produces a sodium ion with a +1 charge and an 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 with strong electrostatic forces of attraction between the oppositely charged ions. Therefore, large amounts of energy are required to break these bonds, contributing to its high melting point.
