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An aluminum atom has the atomic number 13 and the mass number 27 - Edexcel - GCSE Chemistry - Question 9 - 2019 - Paper 1
Question 9
An aluminum atom has the atomic number 13 and the mass number 27. Which row shows the numbers of subatomic particles present in an aluminium ion, Al$^{3+}$? (1) (... show full transcript
Worked Solution & Example Answer:An aluminum atom has the atomic number 13 and the mass number 27 - Edexcel - GCSE Chemistry - Question 9 - 2019 - Paper 1
Step 1
Which row shows the numbers of subatomic particles present in an aluminium ion, Al$^{3+}$?
Answer
An aluminum ion, Al, has lost 3 electrons, so the number of subatomic particles is as follows:
- Protons: 13 (as the atomic number remains unchanged)
- Neutrons: 14 (calculated as mass number 27 - atomic number 13)
- Electrons: 10 (13 original - 3 lost)
So the correct row is: A. 13 14 10.
Step 2
Starting with 1.35g of magnesium, calculate the maximum mass of magnesium oxide that could be formed in this reaction.
Answer
To determine the maximum mass of magnesium oxide (MgO) produced from 1.35g of magnesium, we follow the steps:
-
Calculate moles of magnesium (Mg):
Molar mass of Mg = 24.0 g/mol
Moles of Mg = 1.35 g / 24.0 g/mol = 0.05625 mol
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Use the stoichiometry of the balanced equation:
2 moles of Mg produce 2 moles of MgO. Thus, 0.05625 mol of Mg will also produce 0.05625 mol of MgO.
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Calculate mass of MgO produced:
Molar mass of MgO = 24.0 g/mol (Mg) + 16.0 g/mol (O) = 40.0 g/mol
Mass of MgO = moles × molar mass = 0.05625 mol × 40.0 g/mol = 2.25 g.
Therefore, the maximum mass of magnesium oxide that could be formed is 2.25 g.
Step 3
Step 4
Explain how sodium and chlorine atoms form the ions in sodium chloride and how the ions are arranged in the solid sodium chloride.
Answer
Explanation of Ion Formation
Sodium (Na) and chlorine (Cl) atoms form ions through the transfer of electrons. Sodium has one electron in its outer shell (2.8.1) and chlorine has seven electrons in its outer shell (2.8). To achieve full outer shells, sodium:
- Loses one electron to become a sodium ion (Na) with a charge of +1.
- Gains an electron to become a chloride ion (Cl) with a charge of -1.
Arrangement in Solid Sodium Chloride
In solid sodium chloride (NaCl), the Na and Cl ions are held together by strong ionic bonds. The arrangement of these ions forms a regular lattice structure where:
- Each sodium ion is surrounded by six chloride ions.
- Each chloride ion is surrounded by six sodium ions.
This creates a stable and repeating pattern, maximizing the electrostatic attraction between oppositely charged ions.
Diagrams can be used to illustrate this structure for visual clarity.