CIE iGCSE Co-Ordinated Science C8.5 Noble gases Exam Style Questions Paper 1
▶️ Answer/Explanation
Helium (atomic number 2) has an electron configuration of 2 — its first and only shell is full with 2 electrons, making it completely unreactive; statements 1 and 2 are both correct.
Statement 3 is incorrect (the outer shell is complete, not incomplete), and statement 4 is incorrect (helium is monatomic — He, not He₂).
✅ Answer: (A)
Statement 3 is incorrect (the outer shell is complete, not incomplete), and statement 4 is incorrect (helium is monatomic — He, not He₂).
✅ Answer: (A)
▶️ Answer/Explanation
Argon is a noble gas and is chemically inert, meaning it does not react with the hot filament inside a light bulb.
This makes it ideal for filling filament lamps, providing an unreactive atmosphere that prevents the filament from burning away.
Argon is not used as a catalyst, in alloys, or to neutralise chemical waste, since these uses require reactive or structural properties argon does not have.
✅ Answer: (C)
This makes it ideal for filling filament lamps, providing an unreactive atmosphere that prevents the filament from burning away.
Argon is not used as a catalyst, in alloys, or to neutralise chemical waste, since these uses require reactive or structural properties argon does not have.
✅ Answer: (C)
▶️ Answer/Explanation
Argon is a noble gas with a full outer electron shell, making it chemically unreactive.
This unreactivity means it will not react with the hot filament inside a lamp, preventing it from burning out quickly.
Being a gas or colourless are true but do not explain why it specifically protects the filament.
✅ Answer: (D)
This unreactivity means it will not react with the hot filament inside a lamp, preventing it from burning out quickly.
Being a gas or colourless are true but do not explain why it specifically protects the filament.
✅ Answer: (D)
▶️ Answer/Explanation
Argon is a noble gas with a full outer electron shell, making it chemically unreactive (inert).
Filling lamps with argon prevents the hot filament from reacting with, and burning away in, oxygen from the air.
Its density relative to air is not the reason it is used in lamps.
✅ Answer: (D)
Filling lamps with argon prevents the hot filament from reacting with, and burning away in, oxygen from the air.
Its density relative to air is not the reason it is used in lamps.
✅ Answer: (D)
▶️ Answer/Explanation
Group VIII noble gases have a full outer shell of electrons.
This stable electron arrangement means they have no tendency to gain, lose or share electrons, so they do not readily react.
Being gaseous or monatomic is a physical description, not the reason for their unreactivity.
✅ Answer: (D)
This stable electron arrangement means they have no tendency to gain, lose or share electrons, so they do not readily react.
Being gaseous or monatomic is a physical description, not the reason for their unreactivity.
✅ Answer: (D)