The Periodic Table was developed by Dmitri Mendeleev - Junior Cycle Science - Question 15 - 2019
Question 15
The Periodic Table was developed by Dmitri Mendeleev. It was published 150 years ago in 1869. To celebrate the International Year of the Periodic Table, the European... show full transcript
Worked Solution & Example Answer:The Periodic Table was developed by Dmitri Mendeleev - Junior Cycle Science - Question 15 - 2019
Step 1
Identify a gas which is a component of the Earth’s atmosphere and which is in plentiful supply.
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Answer
The gas that is a component of the Earth’s atmosphere and is in plentiful supply is Nitrogen.
Step 2
Why should the use of the gas helium (He) in birthday balloons be avoided?
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Answer
The use of helium in birthday balloons should be avoided because helium is seriously threatened in availability. It is a non-renewable resource and is being depleted due to various uses, including party balloons.
Step 3
Suggest one way humans could contribute to sustaining levels of this element for future generations.
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Answer
One way humans can contribute to sustaining levels of indium is by recycling electronic devices that contain indium, thereby reducing the need for new mining and ensuring that existing indium is reused.
Step 4
What evidence is there in the diagrams to support the classification of these substances as elements?
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Answer
The evidence supporting the classification of aluminium and chlorine as elements is found in the diagrams, where the particles (or atoms) are represented as uniform in color, indicating they are made up of the same type of particles.
Step 5
Which of these elements is a solid at room temperature? Justify your answer.
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Answer
Aluminium is a solid at room temperature. The particles of aluminium are packed closely together, which is characteristic of solids.
Step 6
Predict the ratio of aluminum to chlorine in this compound.
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Answer
The ratio of aluminum to chlorine in the compound aluminium chloride is 1:3.
Step 7
Write the chemical formula for aluminium chloride.
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Answer
The chemical formula for aluminium chloride is AlCl₃.
Step 8
Which element (1, 2, or 3) is most likely to be a metal? Justify your answer.
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Answer
Element 1 is most likely to be a metal because it has high melting and boiling points (1538 °C and 2862 °C, respectively) and can conduct electricity.
Step 9
Which element (1, 2, or 3) is a liquid at room temperature (20 °C)? Justify your answer.
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Answer
Element 2 is a liquid at room temperature (20 °C) because it has a melting point of -7 °C, which is below room temperature, indicating that it will be in a liquid state.
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