CIE iGCSE Co-Ordinated Science C2.4 Ions and ionic bonds Exam Style Questions Paper 1
Question
Lithium is in Group I and bromine is in Group VII of the Periodic Table.
What is the formula of lithium bromide?
(A) LiBr (B) LiBr2 (C) Li2Br (D) Li2Br2
▶️Answer/Explanation
Ans : A
Question
The diagram represents an ionic compound formed from three types of atom.
What is the chemical formula for this compound?
(A) $Na_{2}S_{4}O$
(B) $NaO_{4}S_{2}$
(C) $Na_{2}SO_{4}$
(D) $S_{4}O_{2}Na$
▶️Answer/Explanation
Ans : C
Question
Which elements react together to form an ionic compound?
(A) carbon and oxygen
(B) nitrogen and hydrogen
(C) potassium and bromine
(D) sodium and lithium
▶️Answer/Explanation
Ans: C
Solution:
Ionic compounds are formed when a metal reacts with a non-metal. Let’s analyze the options:
- (A) Carbon and oxygen:
- Both are non-metals. They form covalent compounds (e.g., CO₂), not ionic compounds.
- (B) Nitrogen and hydrogen:
- Both are non-metals. They form covalent compounds (e.g., NH₃), not ionic compounds.
- (C) Potassium and bromine:
- Potassium is a metal, and bromine is a non-metal. They form an ionic compound (KBr).
- (D) Sodium and lithium:
- Both are metals. Metals do not form ionic compounds with each other.
Correct Answer:
(C) potassium and bromine
- Potassium (a metal) and bromine (a non-metal) react to form the ionic compound potassium bromide (KBr).
Question
Which row describes the physical properties of the named substances?
| substance | solubility in water | electrical conductivity as a solid | electrical conductivity as a liquid | |
|---|---|---|---|---|
| A | ammonia | low | good | good |
| B | copper chloride | high | poor | good |
| C | iron nitrate | high | good | good |
| D | potassium chloride | low | poor | poor |
▶️Answer/Explanation
Answer: B) copper chloride | high | poor | good
Explanation: Copper chloride is highly soluble in water, does not conduct electricity as a solid, but conducts electricity when dissolved in water or in its molten state.
Question
What happens to a tellurium atom when it forms a tellurium ion, \( \text{Te}^{2-} \)?
A. It gains two electrons.
B. It gains two protons.
C. It loses two electrons.
D. It loses two protons.
▶️Answer/Explanation
Answer: A. It gains two electrons.
Explanation: When an atom forms a negative ion, it gains electrons. In this case, tellurium gains two electrons to form \( \text{Te}^{2-} \).
Question
Which diagram represents a fluoride ion?
▶️Answer/Explanation
Answer: D
Explanation: A fluoride ion (F⁻) has gained one electron, giving it a negative charge. Diagram D correctly represents this ion with an extra electron.