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Tamil Nadu Board Class 8 Science Chapter 9 Matter Around Us

if you are looking for Tamil Nadu Board Class 8 Science Chapter 9 Matter Around Us then you are at the right place. Here we are providing solutions as well as additional QA / Important Notes.

 

Choose the best answer.

 

The liquid metal used in thermometers is

  1. a) copper b) mercury c) silver d) gold

 

Which one of the following element name is not derived from planet?

  1. a) Plutonium
  2. c) Uranium
  3. b) Neptunium
  4. d) Mercury

 

Symbol of mercury is

  1. a) Ag
  2. b) Hg
  3. c) Au
  4. d) Pb

 

A form of non-metal which has high ductility is

  1. a) nitrogen
  2. b) oxygen
  3. c) chlorine
  4. d) carbon

 

The property which allows the metals to be hammered into their sheets is

  1. a) ductility
  2. b) malleability
  3. c) conductivity
  4. d) shining strength

 

The non-metal which conducts electric current is

  1. a) carbon
  2. b) oxygen
  3. c) aluminium
  4. d) sulphur

 

Pencil lead contains

  1. a) graphite
  2. c) aluminium
  3. b) diamond
  4. d) sulphur

 

[II] Fill in the blanks.

  1. The element which possesses the character of both metals and non-metals are called___[metalloid]
  2. The symbol of tungsten is____[W]
  3. Melting point of most metal is____than non-metal. [higher]
  4. Water contains_____and______element. [hydrogen and oxygen]
  5. _____is used as semiconductor. [silicon]

 

III. Match the following.

  • Iron   –  For making wires
  • Copper –  Sewing needle
  • Tungsten –  As a fuel for ignition in rocket
  • Boron –  Making the filament of a bulb

 

Iron – Sewing needle

Copper – For making wires

Tungsten – Making the filament of a bulb

Boron – As a fuel for ignition in rocket

 

  • Atom –  Building block of matter
  • Element – Atoms of different kinds
  • Compound –  More than one atom
  • Molecule – Smallest unit of a substance

 

Atom – Building block of matter

Element – Atoms of the same kind

Compound – More than one kind of atom

Molecule – Smallest unit of a substance

 

Answer very briefly.

 

What is ductility?

Ductility is the property of a material, usually a metal, that allows it to be stretched into a thin wire without breaking.

 

Write the constituent elements and their symbols for the following compounds.

  1. a) Carbon monoxide
  2. b) Washing soda
  3. a) Carbon monoxide (CO):

Constituent elements: Carbon (C) and Oxygen (O)

  1. b) Washing soda (Na₂CO₃):

Constituent elements: Sodium (Na), Carbon (C), and Oxygen (O)

 

Write the symbols for the following elements.

  1. a) Oxygen
  2. b) Gold
  3. c) Calcium
  4. d) Cadmium
  5. e) Iron

 

  1. a) Oxygen: O
  2. b) Gold: Au
  3. c) Calcium: Ca
  4. d) Cadmium: Cd
  5. e) Iron: Fe

 

Which non-metal is essential for our life and all living beings?

Oxygen is essential for our life and all living beings.

 

Why are bells made of metals?

Bells are made of metals because metals are sonorous, meaning they produce a clear, resonant sound when struck.

 

What does a chemical symbol represent?

A chemical symbol represents one atom of an element and is a shorthand notation for the element’s name.

 

Give two examples for metalloids.

Silicon (Si) and Boron (B).

 

Mention any three compounds that exist in liquid state.

Water (H₂O), Ethanol (C₂H₅OH), and Acetone (CH₃COCH₃).

 

Write three properties of metalloids.

Metalloids have properties of both metals and non-metals.

They can act as semiconductors (e.g., Silicon and Germanium).

Metalloids are typically brittle and not as malleable or ductile as metals.

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