A.
Choose the correct answer:
1. Brittle
2. Graphite
3. Sulphur, Carbon, Iodine (All of these)
4. Both (b) and (c) (Copper oxide and Copper carbonate)
5. Iron
B. True or False (with corrections):
1. False – Mercury and gallium are liquid metals.
2. True
3. False – Non-metals cannot be used to make wires.
4. False – All metals do not react easily with water to release hydrogen gas.
5. True
C. Match the columns:
1. Drawn into wires – Ductility
2. Beaten into sheets – Malleability
3. Shiny appearance – Lustre
4. Ringing sound – Sonorous
5. Solid, liquid or gas – Physical state
D. Name the following:
1. The metal which is liquid at room temperature – Mercury
2. The non-metal which is hard – Diamond
3. The metal which is soft – Sodium
4. The metal which has low melting and boiling points – Gallium
5. The non-metal which is a good conductor of electricity – Graphite
E. Name the metals and non-metals according to their use:
1. The non-metal used in water purification – Chlorine
2. The metal used in the construction of bridges – Iron
3. The metal used for making packing material for food – Aluminium
4. The non-metal used in the manufacture of fertilizers – Nitrogen
5. The non-metal used as an antiseptic in skin ointments – Iodine
Define the following terms:
1. Metals – Elements that are generally hard, lustrous, malleable, ductile, and good
conductors of heat and electricity.
2. Malleability – The property of metals that allows them to be beaten into thin sheets.
3. Sonority – The property of metals that makes them produce a ringing sound when
struck.
4. Reactivity series – A list of metals arranged in order of their decreasing reactivity.
5. Displacement reaction – A chemical reaction in which a more reactive metal displaces
a less reactive metal from its compound.
Answer the following questions briefly:
1. Why are metals like copper and aluminium used for making wires?
Because they are ductile and good conductors of electricity.
2. Why are the handles of utensils not made of metals?
Metals conduct heat, making it unsafe to use as handles for utensils.
3. Write the chemical reaction depicting the reaction of magnesium with oxygen:
2Mg+O2→2MgO2Mg+O2→2MgO
4. What are noble metals?
Noble metals are metals that resist corrosion and oxidation, like gold and platinum.
5. Why is phosphorus stored under water?
Phosphorus is highly reactive and can catch fire when exposed to air, so it is stored
under water to prevent it from reacting.
Answer the following questions in detail:
1. Differentiate between metals and non-metals on the basis of conductivity of heat
and electricity:
○ Metals are good conductors of heat and electricity (e.g., copper).
○ Non-metals are poor conductors of heat and electricity (e.g., sulfur), except for
graphite, which conducts electricity.
2. What is corrosion? Explain by taking an example of copper:
Corrosion is the gradual deterioration of metals due to a chemical reaction with the
environment.
Example: Copper reacts with moist air to form a green coating of basic copper
carbonate.
3. Differentiate between metals and non-metals on the basis of their reaction with
oxygen:
○ Metals react with oxygen to form basic oxides (e.g., magnesium oxide).
○ Non-metals react with oxygen to form acidic oxides (e.g., sulfur dioxide).
4. Show how different metals react with water:
○ Sodium reacts vigorously with water to form sodium hydroxide and hydrogen gas.
○ Magnesium reacts slowly with water to form magnesium hydroxide and hydrogen
gas.
5. What happens when:
○ Copper reacts with iron sulfate? – No reaction occurs because copper is less
reactive than iron.
○ Iron reacts with copper sulfate?
Fe+CuSO4→FeSO4+CuFe+CuSO4→FeSO4+Cu
○ Aluminium reacts with zinc sulfate? – No reaction because aluminium is
higher in the reactivity series.
○ Calcium reacts with sodium sulfate? – No reaction occurs because both
calcium and sodium form soluble compounds.
6. Write word equations for all the above cases:
○ Iron + Copper sulfate → Iron sulfate + Copper
○ Sodium + Water → Sodium hydroxide + Hydrogen
○ Magnesium + Water → Magnesium hydroxide + Hydrogen
