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Which graph correctly shows the relative melting points of the elements Mg, Al, Si and P plotted against their relative first ionisation energies? A B - CIE - A-Level Chemistry - Question 13 - 2017 - Paper 1
Question 13
Which graph correctly shows the relative melting points of the elements Mg, Al, Si and P plotted against their relative first ionisation energies? A B
Worked Solution & Example Answer:Which graph correctly shows the relative melting points of the elements Mg, Al, Si and P plotted against their relative first ionisation energies? A B - CIE - A-Level Chemistry - Question 13 - 2017 - Paper 1
Step 1
Identify the Elements and Their Trends
Answer
The elements in question are magnesium (Mg), aluminum (Al), silicon (Si), and phosphorus (P). To analyze their melting points and first ionization energies, we need to consider the general trends in the periodic table.
- Melting point typically increases across periods and decreases down groups.
- First ionization energy generally increases across a period and decreases down a group.
Step 2
Analyze Melting Points and Ionization Energies
Answer
- Magnesium (Mg): Has a high melting point and moderate ionization energy.
- Aluminum (Al): Moderate melting point and ionization energy.
- Silicon (Si): Higher melting point than aluminum, but lower ionization energy compared to magnesium.
- Phosphorus (P): Lower melting point and ionization energy.
Step 3
Evaluate Graph Options A and B
Answer
Graph A should plot Si highest on melting point but not correctly positioned with Mg, while Al should be lower than Si. Graph B places Al correctly regarding its relative position of melting point and first ionization energy. Therefore, the correct graph that shows these relationships is Graph B.
Step 4