This question is about oxygen and substances containing oxygen - AQA - GCSE Chemistry - Question 3 - 2017 - Paper 1
Question 3
This question is about oxygen and substances containing oxygen.
3 (a) (i) Complete Figure 4 to show the arrangement of the outer shell electrons in an oxygen molecu... show full transcript
Worked Solution & Example Answer:This question is about oxygen and substances containing oxygen - AQA - GCSE Chemistry - Question 3 - 2017 - Paper 1
Step 1
Complete Figure 4 to show the arrangement of the outer shell electrons in an oxygen molecule.
96%
114 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
In an oxygen molecule (O₂), each oxygen atom has 6 outer shell electrons. Using dots (•) for one oxygen atom and crosses (×) for the other, the arrangement will be:
• • • • • •
× × × × × ×
Each molecule shares a pair of electrons to form a double bond.
Step 2
Name the type of bonding in an oxygen molecule.
99%
104 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
The type of bonding in an oxygen molecule is covalent bonding. In this bonding, the atoms share pairs of electrons.
Step 3
Explain why oxygen has a low boiling point.
96%
101 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
Oxygen has a low boiling point due to weak intermolecular forces between the molecules. These weak van der Waals forces require little energy to overcome, allowing the molecules to easily transition from liquid to gas at low temperatures.
Step 4
Balance the equation for the reaction.
98%
120 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
The balanced equation for the reaction of magnesium and oxygen is:
2Mg+O2→2MgO
Step 5
Describe what happens, in terms of electrons, when magnesium atoms react with oxygen atoms to produce magnesium oxide.
97%
117 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
When magnesium reacts with oxygen, magnesium loses two electrons to achieve a stable electron configuration, resembling that of a noble gas. Meanwhile, oxygen gains these two electrons, resulting in a full outer shell. This transfer creates magnesium ions (Mg²⁺) and oxide ions (O²⁻), which are held together by ionic bonds due to electrostatic attraction.
Step 6
What are nanoparticles?
97%
121 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
Nanoparticles are particles that range from 1 to 100 nanometers in size. They often contain a few hundred atoms and have a high surface area to volume ratio, which gives them unique properties compared to bulk materials.
Step 7
Explain, in terms of structure and bonding, why silicon dioxide is used to line furnaces.
96%
114 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
Silicon dioxide (SiO₂) has a high melting point because it forms a giant covalent structure, where each silicon atom is bonded to four oxygen atoms and vice versa. This strong bonding requires a significant amount of energy to break, making it ideal for use in high-temperature applications such as furnaces.
